GIFT 


Miss  Prances  M.  Molera 


From  the  collection  of  the 


Z 


Prelinger 
v    JJibrary 
t         p 


San  Francisco,  California 
2006 


I 


FIG.  i.  —  See  p.  59. 
AGES.    PERIODS.     GROUPS  AND  ROCKS. 


Vegetable  soil. 

A  lluvial.  —  Clay,    sand, 

and  gravel. 
Drift.  —  Clay,  gravel,  and 

bowlders. 


Pliocene.  —  Sands,    clays, 
and  marls. 

Miocene.  —  Marls,     lime- 
stones, &c. 

Eocene.  —  Clays,    sand- 
stones, &c. 


5  E 


21 


Chalk.  —  Flint,  greensand, 
limestones. 

Wealden. 

Oolite.  —  Shales  and  lime- 
stone. 

Lias.  —  Shales. 

Trias.  —  Red  sandstones 
and  saliferous  marls. 


Magnesian  limestones  and 

red  sandstones. 
Shales. 


Coal-Measures. 
Alternating  sandstones, 
shales,  and  coal-beds. 
Cavernal  limestone, 
Conglomerate. 


a?  Sandstone. 
Chemung.  —  Shales. 
Hamilton.  —  Shales. 
Corniferous.— Limestones. 
Oriskany  Sandstone. 


Lower  Helderberg. 

Saliferous.  —  Marls. 

Niagara. 

Oneida. 

Hudson. 

Trenton  Limestone. 

Potsdam  Sandstone. 


•tt 


Crystallized    limestones, 
gneiss,  and  quartzite. 


OUR  PLANET, 


ITS 


PAST  AND    FUTURE; 


OH, 


LECTURES  ON  GEOLOGY. 


BY 

WILLIAM   DENTON. 


SIXTH    THOUSAND. 


BOSTON: 
WILLIAM    DENTON,    PUBLISHER 

1873. 


Entered,  according  to  Act  of  Congress,  in  the  year  1868,  by 

WILLIAM   DENTON, 
In  the  Clerk's  Office  of  the  District  Court  of  the  District  of  Massachusetts 


GEO.  C.  RAND  &  AVERY, 

STBRBOTYPERS  AND  PRINTERS 

3  CORNKJLL,  BOSTON. 


PREFACE, 


WHILE  lecturing  upon  Geology,  which  I  have  done  for  the 
last  thirteen  years,  in  various  parts  of  the  United  States  and 
Canada,  I  have  been  requested  many  times  to  write  a  vol- 
ume embodying  the  substance  of  my  lectures,  so  that  those 
who  had  heard  them  in  public  might  be  able  to  read  and 
study  them  in  private.  In  accordance  with  their  request,  I 
have  written  this  volume ;  divesting  it,  as  I  do  my  lectures, 
as  far  as  possible,  of  the  technicalities  by  which  the  science 
of  Geology  is  so  frequently  obscured,  and  presenting  it  in  the 
same  order  in  which  it  is  presented  by  Nature  herself. 

I  am  indebted  to  Lyell,  Owen,  Mantell,  Buckland,  Ansted, 
Hall,  Dana,  and  many  others ;  and  have  freely  used  their 
works,  as  they  had  done  the  writings  of  previous  authors. 

I  am  also  indebted  to  Prof.  Henry  A.  Ward  of  Rochester 
for  copies  of  engravings  contained  in  his  "  Catalogue  of  Casts 
of  Fossils."  At  vast  expense,  and  by  years  of  persevering 
labor,  directed  by  rare  ability  and  scientific  culture,  he  has 
collected  many  hundreds  of  rare  and  unique  fossils  and  casts, 
to  the  great  advancement  of  Geology  in  America. 

W.  D 

WELLESLEY,  June  17,  1868. 


M505440 


6  CONTENTS. 

Red  Sandstone  or  Trias.  —  Salt  and  its  Formation.  —  How  the 
Sea  became  Salt.  —  Gypsum  and  its  Formation.  —  Footprints  of 
the  Connecticut  Valley.  —  The  Valley  and  its  Inhabitants  in  this 
Period.  —  How  the  Footprints  were  made.  —  First  Mammals  .  126 

LECTURE  IV. 

Granite  not  always  the  Oldest  Rock.  —  Metamorphic  Rocks  produced 
during  all  Ages.  —  Rocks  frequently  wanting.  —  The  Cause  of 
this.  —  Lias.  —  Age  of  Reptiles. — Ichthyosaurus.  —  World  never 
made  "just  as  it  is." — Plesiosaurus.  —  Pterodactyle.  —  Plants, 
Insects,  and  Shells  of  the  Lias. — Poetry  in  Geology.  —  Oolite. — 
Jurassic  Formation.  —  Beds  and  Fossils  of  Solenhofen.  —  Port- 
land Dirt-Bed.  —  Wealden.  —  Iguanodon  and  other  Large  Sau- 
rians.  —  Why  Reptiles  were  Larger  in  Past  Times.  —  Cretaceous 
Formation.  —  Production  of  Chalk  and  Flint.  —  Cretaceous  De- 
posits of  Europe  and  America.  —  Texas  and  Colorado  Beds  of 
this  Age.  —  Sponges,  Shells,  Reptiles,  and  Mammals  of  the 
Cretaceous  Period.  —  Tertiary  Formation.  —  Eocene.  —  London 
Clay  and  its  Fossils. — Paris  Basin. — Alabama  Beds.  —  Zeuglo- 
don.  —  Beds  of  Brandon,  Vt.  —  Miocene.  —  Bad  Lands  of  Ne- 
braska. —  White-river  Basin.  —  Fossil  Insects.  —  Appearance  of 
White-river  District.  —  Martha's  Vineyard.  —  Beds  of  Northern 
Greenland.  —  Beds  of  (Eningen  and  their  Fossils.  —  Amber. — 
Fossil  Fishes  of  Monte  Bolca.  —  Scheachzer's  Witness  of  the 
Deluge.  —  Deinotherium.  —  Mastodon.  —  Fossil  Horse.  —  Mon- 
keys in  France  and  Greece.  —  Pliocene. — Progress  during  the 
Tertiary  Period.  —  Beds  of  the  Sewalik  Hills,  and  Fossil  Reptiles 
and  Mammals  found  in  them.  —  Tertiary  Deposits  of  Colorado.  — 
Megatherium  and  Allied  Forms  of  South  America.  —  Correspond- 
ence between  Recent  Tertiary  Animals  and  those  living.  —  Re- 
sent Deposits  and  Fossils  of  Australia,  New  Zealand,  and  Mada- 
gascar. —  Monkeys  of  France  and  South  America  .  .  .  1 69 

LECTURE  V. 

A  Backward-looking  Time.  —  Drift  or  Glacial  Period.  —  Universal 
Flood  Impossible.  —  Drift-Beds  made  by  Action  of  Ice.  —  Theo- 
ries formed  to  account  for  the  Extreme  Cold.  —  Fossil  Remains 
found  in  the  Drift.  —  Mammoth  of  Siberia.  —  Irish  Deer.  —  Kirk- 
dale  Cave.  —  Kent's  Hole.  —  Remains  of  Man  in  Connection  with 
those  of  Extinct  Animals.  — Flint  Implements  of  the  Somme  Val- 


CONTENTS.  7 

ley. — Picture  of  the  Early  Men.  —  Inferior  Heads  of  the  "  Stone 
Men  "  of  Europe.  —  Terrace  Period.  —  Alluvial  Formation.  — 
Operations  of  the  Ocean  on  the  Coast  of  the  United  States,  Scot- 
land, and  England.  — Land  Forming.  —  The  Deltas  of  the  Missis- 
sippi, Nile,  Po,  and  Ganges.  —  Nature's  Diary.  —  Land  elevated. 
—  Its  Varied  Surface  secured  for  Ages 243 

LECTURE  VI. 

Tendency  of  Mankind  to  look  into  the  Future.  —  The  Future  can  be 
foretold.  —  The  Earth  will  endure  for  Millions  of  Years.  —  It  will 
Improve.  —  Volcanoes  will  die,  and  Earthquakes  cease.  —  Land- 
Surface  will  be  increased.  —  Climate  probably  improve.  —  Weeds, 
Troublesome  Beasts,  and  Poisonous  Reptiles,  will  cease  to  exist.  — 
Agency  of  Man  in  producing  these  Results.  —  Where  Fuel  will  be 
obtained  in  the  Coming  Time. — Increase  of  Population.  —  Means 
of  Subsistence.  —  Man  the  Noblest  Being  that  will  ever  live  on  this 
Planet.  —  The  Reason.  —  The  Destiny  of  the  Earth  .  .  .289 


LECTUEES  ON  GEOLOGY. 


LECTURE    I. 

THIS  is  a  wonderful  and  beautiful  world  on  whose 
surface  we  live.  There  are  mountains  whose  hoary 
summits  are  lost  in  the  clouds  that  envelop  them ; 
grassy  valleys  lying  in  beauty  at  their  feet;  deep  can- 
yons that  the  sun  never  visits,  through  which  flow 
rushing  torrents  continually;  lakes  that  sleep  in  the 
arms  of  verdant  hills ;  rills  that  leap  with  tinkling  feet 
over  mossy  ledges;  and  oceans  tossing  in  their  resist- 
less might,  and  grinding  to  powder  the  precipices  that 
gird  them. 

What  a  multitude  and  variety  of  organic  existences 
we  behold  !  —  tall  pines  rearing  their  graceful  heads  on 
the  hills;  mosses  carpeting  the  damp  ground  in  the 
vales ;  eagles  soaring  above  the  clouds  ;  humming-birds 
flitting  from  flower  to  flower;  deer  bounding  through 
the  forest  -  glades ;  squirrels  skipping  from  bough  to 
bough ;  whales  floating  like  islands  in  the  ocean ;  animal- 
cules exploring  a  drop ;  and,  considering  all  these,  manj 
upright-standing,  upward-looking,  the  fruit  of  the  ages 
and  the  brain  of  the  world. 

Nor  is  this  all :  where  the  interior  of  the  earth  is  ex- 


10  LECTURES  ON   GEOLOGY. 

posed  to  our  view,  we  discover  beds  of  clay,  —  red,  blue, 
white,  and  yellow;  sand,  gravel,  marl;  and  more  solid 
beds  of  shale,  slate,  sandstone,  conglomerate,  limestone, 
marble,  trap,  and  granite.  In  some  of  these,  we  find 
leaves  of  trees,  shells  and  fishes,  and  bones  of  reptiles, 
birds,  and  beasts. 

Who  is  so  incurious  as  not  to  desire  to  know  the  his- 
tory of  all  these  ?  Who  does  not  wish  to  know  how  and 
when  these  mountains  were  heaved,  and  they  first  looked 
proudly  up  at  the  stars  above  them,  and  down  on  the 
world  that  lay  sleeping  at  their  feet?  when  the  rivers 
first  coursed  down  their  slopes,  and  commenced  the 
work  of  carrying  them  to  the  ocean  ?  when  those  can- 
yons were  carved,  and  what  carved  them  ?  when  came 
into  being  the  grasses  and  trees,  the  fishes  and  beasts  ? 
and  how  myriads  of  them  became  embedded  in  the  vari- 
ous rocks  in  which  their  remains  are  found?  Who 
would  not  learn  the  history  of  this  great  world  and  its 
wonders  ? 

Where  is  the  book,  you  eagerly  inquire,  in  which  this 
history  is  recorded  ?  There  is  no  volume  of  man's  mak- 
ing in  which  it  may  be  found ;  no  library  could  contain 
the  thousandth  part  of  it :  but  it  is  inscribed  on  the 
rocks  around  us  and  beneath  our  feet;  they  constitute 
the  volume  you  wish  to  read,  every  word  of  which  is 
written  by  Nature's  own  hand.  She  has  kept  a  faith- 
ful record  of  all  her  doings,  —  kept  with  wonderful 
accuracy  her  diary ;  and  we  may  read  her  own  state- 
ment of  facts  more  wonderful  than  the  fictions  of  Arabian 
fancy.  All  unconsciously,  the  fiery  volcano  has  traced 
its  turbulent  history  with  a  burning  pen ;  the  coral  and 
the  sea-weed,  the  fishes,  reptiles,  birds,  and  beasts  of 
the  olden  time  have  written  their  life-story  in  the  plastic 


LECTURES  ON  GEOLOGY.  11 

rock,  for  us  to  read.  All  is  recorded  in  them  that  hag 
been  done  to  bring  the  world  from  the  original  rude 
state  in  which  it  existed  to  the  condition  of  life  and 
beauty  that  crowns  it  to-day.  How  glad  should  we  be  to 
have  the  privilege  of  reading  this  wonderful  book,  and 
of  becoming  familiar  with  its  contents  ! 

Men  have  read  and  studied  this  great  volume  for 
years ;  and  the  science  of  geology  includes  what  they 
have  discovered  in  it.  This  science,  dry  as  some  per- 
sons deem  it,  is  second  in  interest  to  none,  and  is  worthy 
of  the  consideration  of  all. 

The  farmer  should  study  geology ;  for  it  treats  of 
what  most  intimately  concerns  him.  "  What  has  a 
farmer  to  do,  with  ologies  ?  "  says  one.  Farmers  would 
be  better  men,  as  well  as  better  farmers,  if  they  knew 
more  about  the  "  ologies."  "  What  is  this  through 
which  your  ploughshare  is  moving  from  day  to  day,  and 
from  which  all  your  wealth  is  obtained?'7  The  farmer 
answers,  "  Dirt  or  soil."  —  "And  how  do  you  think  it 
was  made  ?  "  —  "  Oh  !  I  don't  know  :  made  when  the 
world  was  made,  I  suppose."  Take  a  pinch  of  this  soil, 
place  it  under  a  magnifying-glass,  and  you  discover  a 
gravel-bank.  Most  of  the  soil  is  made  up,  you  find,  of 
small  stones  formed  by  the  wearing-down  of  solid  rocks 
as  hard  as  the  bowlder  by  the  roadside.  By  the  con- 
stantly-falling rains,  by  roaring  torrents,  by  grinding 
glaciers,  by  swelling  frosts,  and  blowing  winds,  the  solid 
rocks  have  been  ground  during  ages  to  powder ;  and 
the  soil  is  that  powder.  The  soil  is  therefore,  at  fill 
times,  like  the  rock  of  which  it  was  made.  Where  sand- 
stone has  been  worn  down  to  make  soil,  we  have  sandy 
soil  as  the  result;  where  shaly  rocks  have  been  thus 
worn  down,  we  have  stiff,  clayey  soils ;  and  the  wearing* 


12  LECTURES    ON   GEOLOGY. 

down  of  limestones  and  shales  together,  as  in  Illinois 
and  Kansas,  gives  us  rich,  loamy  soils  abounding  with 
the  elements  of  fertility.  So  much  do  the  soils  resemble 
the  rocks  from  which  they  are  derived,  that  in  chalky 
districts  the  soil  is  white,  red  in  the  red  sandstone 
region,  and  generally  of  nearly  the  same  color  as  the 
rock  from  which  it  was  formed. 

By  consulting  a  geological  map,  and  thus  obtaining  a 
knowledge  of  the  rocks  found  in  certain  districts,  we 
may  know  before  we  visit  them  the  character  of  their 
soils,  to  what  crops  they  are  best  adapted,  and  what 
districts  of  country  will  sustain  the  largest  population. 

The  farmer  is,  of  course,  interested  in  what  lies 
beneath  the  soil,  especially  if  he  is  the  owner  of  his 
farm.  Few  farmers  dream  of  the  extent  and  value  of 
their  possessions.  They  know  how  long  their  farms  are, 
and  just  how  broad ;  but  how  many  farmers  think  that 
their  farms  are  four  thousand  miles  thick,  and  all  theirs  ? 
Immediately  beneath  the  soil  may  lie  just  what  the  hun- 
gry surface  needs  to  enrich  it :  geology  frequently  points 
this  out.  Thus  in  the  southern  part  of  New  Jersey, 
where  the  soil  is  much  like  the  sea-beach,  little  better 
than  shifting  sand,  marl,  or  green  sand  as  it  is  termed, 
was  found  underlying  this ;  and,  on  being  laid  on  the 
land,  the  result  was  a  great  increase  in  its  productive- 
ness :  so  that,  as  Prof.  Rogers  says,  "  land,  which,  pre- 
vious to  the  discovery  of  the  green  sand,  sold  for  two 
dollars  and  a  half  the  acre,  was  subsequently  worth 
thirty-seven  dollars  the  acre."  So  much  has  Geology 
done  for  the  New-Jersey  farmer ;  and  she  is  prepared  to 
do  as  much  for  many  more. 

Where  lie  the  stores  of  mineral  wealth  ?  —  of  coal,  iron, 
copper,  and  more  precious  metals  that  have  been  con- 


LECTURES   ON   GEOLOGY.  13 

cealed  in  the  dark  recesses  of  the  earth  for  ages  ?  The 
farmer  and  the  miner  are  equally  interested  in  the 
answer  to  this  question.  Geology,  by  teaching  us  what 
rocks  do  not  contain  certain  minerals,  prevents  much 
useless  expenditure  of  time  and  money;  and,  by  point- 
ing out  the  rocks  in  which  they  are  likely  to  be  found, 
sometimes  enables  the  miner  to  dig  with  confidence,  and 
reap  the  fruit  of  his  labors. 

In  Canada,  an  ignorant  farmer  complained  of  a  sin- 
gular green  soil  upon  his  farm,  from  which  he  could 
obtain  nothing  but  a  few  waxy  potatoes.  A  practical 
Iran  of  my  acquaintance,  with  some  knowledge  of 
geology,  saw  this  soil,  and  knew  at  once  the  cause  of  its 
greenness.  Some  of  that  very  soil  was  sold  by  him  for 
twenty  dollars  a  barrel ;  and  where  the  soil  refused  to 
produce  good  potatoes  is  now  a  famous  copper-mine. 
Many  a  farmer  who  never  saw  deeper  into  his  farm  than 
the  bottoms  of  his  ditches  is  complaining  bitterly  of  his 
poverty  ;  while  within  twenty  feet  of  his  nose  lies  what 
would  make  him  richer  than  Croesus. 

To  the  philosopher,  geology  is  of  incalculable  value. 
No  science  digs  deeper,  few  soar  higher.  Do  you  want 
a  foundation  for  your  philosphy, deep,  abiding:  here  you 
may  find  it.  For  want  of  it,  our  so-called  philosophies 
are  castles  of  cards,  erected  to-day,  blown  down  to-mor- 
row. If  history,  written  by  the  fallible  finger  of  man, 
and  extending  over  but  two  or  three  thousand  years, 
is  so  important  that  men  wisely  spend  a  lifetime  in  its 
study,  how  much  more  important  a  history  of  events 
transpiring  during  countless  ages,  written  by  impartial 
historians,  who  have  infallibly  recorded  the  facts  of  the 
past !  More  than  the  telescope  to  the  astronomer,  and 
the  microscope  to  the  naturalist,  is  this  science  to  the 


14  LECTURES   ON   GEOLOGY. 

philosopher.  Mysteries  that  it  once  seemed  impossible 
to  discover  are  plain  to  his  illumined  vision;  and,  where 
he  saw  through  the  fog  but  the  dim  outline,  the  land- 
scape now  lies  before  him  in  the  glowing  sunshine. 

Geology  should  be  studied ;  if  for  no  other  reason,  for 
the  happiness  that  it  affords.  AM  knowledge  increases 
our  capacity  for  enjoyment ;  opens  new  windows  to  the 
soul,  through  which  the  sunlight  of  bliss  may  beam ;  and 
yields  to  the  true-hearted  student  the  purest  pleasure. 

Wearily  and  sadly  the  laborer  toils  in  the  quarry,  dig- 
ging rock  for  the  lime-kiln.  He  goes  to  his  work  as  the 
remanded  prisoner  to  his  dungeon,  without  pleasure  or 
hope.  The  rocks  are  hard,  and  very  useful  when  burned 
into  lime,  —  the  sum  total  of  his  knowledge  with  regard 
to  them.  But  a  volume  on  geology,  is  placed  in  his 
hands,  and  it  opens  his  eyes.  He  discovers  that  every 
rock  he  handles  is  written  within  and  without  with  mys- 
terious characters,  whose  significance  he  may  learn  :  he 
deciphers  them  day  by  day,  and  is  delighted  with  the 
knowledge  which  they  disclose ;  every  move  of  his 
crowbar  turns  over  a  new  leaf;  and  he  finds  himself  a 
happy  student  in  Nature's  college,  furnished  with  an 
excellent  library  and  the  best  of  professors,  who  do  not 
despise  him  for  his  thread-bare  coat  or  "  clouted  shoon." 

Destitute  of  astronomy,  the  heavens  would  be  to  us  a 
sealed  book,  the  moon  no  larger  than  a  dinner-plate,  and 
the  stars  but  shining  points  in  the  revolving  sky.  But, 
with  the  light  that  this  noble  science  sheds,  we  behold 
the  rolling  worlds  around  us,  and  view  with  mingled 
awe  and  delight  the  midnight  vault  that  bends  over  us. 
And  what  astronomy  does  for  the  heavens,  geology  does 
for  the  earth,  and  much  more.  These  pebbles  we 
trample  under  foot  are  volumes  that  we  may  read  with 


LECTURES   ON  GEOLOGY.  15 

profit  and  pleasure :  they  are  travellers  who  have  wan- 
dered over  many  lands ;  and  they  have  wonderful 
stories  to  tell  us  when  we  have  learned  their  language. 
I  make,  therefore,  no  more  apology  for  introducing  this 
science  of  geology  to  your  notice,  assured  that  it  will 
amply  repay  you  for  your  most  devoted  attention. 

On  examining  the  earth's  surface  for  the  purpose  of 
discovering  how  it  came  into  its  present  condition,  we 
soon  learn  that  water  has  been  an  active  operator. 
Around  us  lie  pebbles,  every  one  of  which  came  into  its 
present  rounded  form  by  being  rolled  in  water ;  for 
every  pebble  was,  without  doubt,  once  part  of  a  solid 
rock,  which  has  been  broken  off,  and  rolled  over  and 
over  till  it  acquired  its  present  shape.  Even  on  the 
tops  of  hills  we  find  beds  of  gravel,  sand,  and  clay. 
The  sand  was  once  quartz  or  sandstone,  and  has  been 
worn  into  its  present  condition  by  running  rivers,  or 
rolled  by  the  waves  of  lakes  or  oceans ;  while  the  clay 
or  mud  has  been  formed  from  shaly  or  slate-rocks  in  a 
similar  way.  The  few  exceptions  to  this  I  shall  treat 
of  in  a  future  lecture. 

We  see  at  a  glance,  then,  either  that  the  water  has 
been  high  as  the  hills,  or  the  hills  have  been  low  as  the 
water.  If  we  dig  below  these  loose  beds,  we  shall  find 
in  many  places  layers  of  sandstone,  shale,  conglomerate, 
and  limestone.  The  sandstone,  we  shall  discover,  after 
some  study,  was  once  sand;  the  shale  was  once  mud 
or  clay ;  and  the  conglomerate,  or  pudding-stone  as  it  is 
sometimes  called,  is  merely  pebbles  cemented  together. 
In  these  beds  we  find  leaves  and  branches  of  trees  that 
once  floated  on  the  water,  and  shells  that  once  lived  in 
it.  At  the  bottoms  of  coal-mines,  from  one  to  two  thou- 
sand feet  deep,  we  may  see  such  rocks  and  such  remains 


16  LECTURES   ON  GEOLOGY. 

in  them  ;  and,  in  many  places  where  rocks  have  been 
lifted  up  and  exposed,  such  beds  have  evidently  been  at 
one  time  much  deeper  than  this,  —  some  of  them  miles 
in  depth. 

When  we  learn  these  facts,  we  cannot  be  much  sur- 
prised that  early  geological  investigators  came  to  the 
conclusion  that  the  whole  crust  of  the  globe  had  been 
deposited  as  sediment  at  the  bottom  of  a  mighty  ocean, 
at  one  time  covering  the  whole  earth:  in  other  words, 
they  supposed  that  water  had  been  the  sole  agent  em- 
ployed in  bringing  the  earth  into  its  present  condition. 
But  a  more  extended  and  thorough  investigation  soon 
showed  them  that  this  was  a  one-sided  view  of  the  mat- 
ter, and  that  another  important  agent  had  also  been 
employed. 

In  the  neighborhood  of  volcanoes  were  found  beds  of 
ashes,  cinders,  and  hardened  lava :  no  one  could  dispute 
that  these  were  made  by  fire.  At  a  distance  from  all  vol- 
canoes, beds  similar  to  these  were  found,  that  were  also 
evidently  fire-made.  In  England,  where  geological  in- 
vestigations were  carried  on  a  long  time  ago,  and  where 
there  is  at  this  time  no  volcano,  rocks  similar  to  the 
lavas  of  JEtna  and  Vesuvius  were  found.  Between 
Whitby  and  Scarborough,  on  the  Yorkshire  coast,  is 
what  is  called  a  trap-dike,  extending  in  a  north-western 
direction  for  fifty  or  sixty  miles  :  it  is  about  thirty  feet 
wide  generally ;  but,  in  places  where  the  lava  had  evi- 
dently overflowed,  I  have  seen  it  a  hundred  yards  wide. 
This  dike  is  a  crevice,  filled  with  what  was  once  melted 
matter,  either  poured  out  of  some  extinct  volcano,  or 
forced  up  from  below:  for,  where  it  comes  in  contact 
with  limestone,  it  is  either  burnt  into  lime,  or  hardened 
into  a  substance  like  marble  ;  where  it  is  in  contact  with 


LECTURES   ON  GEOLOGY.  17 

coal,  the  coal,  for  several  feet  from  it,  is  converted  into 
soot,  but  at  a  greater  distance  into  anthracite  coal,  and 
at  fifty  feet  is  unaltered.  This  rock,  then,  was  made  by 
fire.  Rocks  similar  to  it  in  composition  are  found  in 
nearly  all  countries,  and,  like  it,  are  evidently  fire-made. 

The  Palisades,  on  the  Hudson,  opposite  New  York, 
are  made  of  this  kind  of  rock.  I  have  seen  dikes  of  it 
around  Lexington,  Waltham,  and  Needham,  in  Massachu- 
setts. In  Nova  Scotia,  there  is  a  bed  of  trap  (as  these 
ancient  lavas  are  called)  one  hundred  and  twenty 
miles  long,  and  from  one  to  six  miles  broad,  —  once,  evi- 
dently, larger  ;  but  much  of  it  has  been  washed  away  by 
the,  waters  of  the  Bay  of  Fundy,  masses  from  the 
undermined  cliffs  falling  continually.  West  of  the 
Rocky  Mountains,  thousands  of  square  miles  are  cov- 
ered with  lava-beds  thousands  of  feet  in  thickness, 
appearing,  in  many  places,  as  if  they  had  been  poured 
out  but  yesterday. 

The  more  geologists  became  familiar  with  the  earth's 
crust,  the  more  apparent  to  them  became  the  evidence 
of  the  operation  of  fire.  They  found  a  large  class  of 
rocks  which  were  crystallized,  and  in  this  respect 
differed  from  recent  lavas,  but  in  every  other  respect 
resembled  them.  There  were  no  sedimentary  lines  in 
them,  indicating  the  action  of  water,  as  we  find  in  the 
water-made  rocks:  and  they  were  at  length  classed 
with  the  fire-made  rocks ;  for  it  appeared  that  they  had 
slowly  cooled  at  great  depths,  and  thus  received  their 
crystalline  form.  The  fire-made  rocks  were  found,  as  a 
rule,  to  underlie  the  water-made  rocks  :  and  at  last  it 
became  apparent,  that,  at  some  time  in  the  immensely- 
distant  past,  the  whole  earth  had  been  in  an  intensely- 
heated  condition,  —  in  fact,  a  molten  mass;  and  that 
2 


18  LECTURES   ON   GEOLOGY. 

rocks  of  great  thickness  had  been  formed  from  the  cool 
ing  of  this  fiery  fluid,  before  water  existed  on  its  sur- 
face. You  may  ask  what  led  geologists  to  come  to  such 
a  conclusion  as  that.  I  will  tell  you  ;  for  this  is  of  the 
greatest  importance.  Once  let  it  be  understood  that  the 
earth  was  originally  a  fiery  mass,  and  we  can  then  learn 
how  naturally  it  has  come  into  its  present  condition,  and 
see  the  reason  for  a  thousand  facts  that  come  before  us, 
otherwise  dark  and  mysterious. 

First,  the  temperature  of  the  earth  steadily  increases 
with  depth.  If  we  were  to  sink  a  well  in  Massachusetts 
to  a  depth  of  sixty  feet,  a  thermometer  at  the  bottom, 
carefully  preserved  from  the  surface  heat  and  cold,  would 
show  no  change  of  heat  throughout  the  year  ;  for,  at  that 
depth,  neither  the  heat  of  summer  nor  the  cold  of  winter 
produces  any  sensible  effect.  A  Fahrenheit  thermome- 
ter would  indicate  there  about  fifty  degrees  of  heat :  but, 
on  going  down  fifty  feet  farther,  we  should  find  the 
mercury  in  the  thermometer  rise  to  about  fifty-one  de- 
grees ;  fifty  feet  farther  still,  fifty-two  degrees ;  and,  as 
we  continued  to  go  down,  we  should  find  the  heat  con- 
tinue to  rise  at  the  rate  of  about  one  degree  for  every 
fifty  feet. 

Experiments  establishing  this  increase  of  heat  with 
descent  have  been  made  in  many  parts  of  the  earth,  — 
on  the  frigid  steppes  of  Siberia,  in  the  mines  of  temper- 
ate England,  and  within  the  torrid  zone.  There  is  a  well 
at  Jakutsk,  in  Northern  Siberia,  dug  through  frozen 
ground  to  a  depth  of  three  hundred  and  eighty-two  feet. 
At  a  depth  of  fifty  feet,  the  temperature  was  seventeen 
degrees,  and  at  the  bottom  it  was  twenty-six  degrees ; 
being  an  increase  of  one  degree  for  about  thirty-seven 
feet :  and,  at  the  same  rate,  it  would  require  a  still 


LECTURES  ON  GEOLOGY.  19 

farther  depth  of  more  than  two  hundred  feet  to  reach 
ground  free  from  the  influence  of  frost. 

At  Sunderland,  in  England,  there  is  a  coal-mine,  a  part 
of  whose  workings  are  fifteen  hundred  feet  below  the 
level  of  the  sea ;  and  there  the  increase  of  heat  is  one 
degree  for  every  fifty-nine  feet. 

At  the  Guanaxato  silver-mine,  in  Mexico,  the  mean 
temperature  at  the  surface  is  sixty-eight  degrees  j  and 
at  the  depth  of  1,713  feet  the  temperature  is  ninety-eight 
degrees,  being  an  increase  of  a  little  more  than  one 
degree  for  every  forty-five  feet.  Humboldt,  in  his  "  Cos- 
mos," says,  "  It  is  worthy  of  notice,  that,  wherever  the 
observations  have  been  conducted  with  care  and  under 
favorable  circumstances,  the  increase  of  the  temperature 
with  the  depth  has  been  found  to  present,  for  the  most 
part,  very  closely  coinciding  results,  even  at  very  differ- 
ent localities."  Prof.  Phillips  says,  "It  appears,  then, 
fully  ascertained,  that  in  situations  far  removed  from 
volcanic  action,  in  different  kinds  of  rock,  with  very 
different  chemical  relations,  water,  air,  and  rocks  contin- 
ually grow  warmer  as  we  descend  in  the  earth.  Without 
a  single .  exception,  the  interior  of  the  globe  is  warmer 
than  the  surface;  and  the  heat  augments  constantly  with 
the  depth." 

In  the  English  coal-mines,  at  a  depth  of  six  or  seven 
hundred  feet,  the  miners  find  a  comfortable  summer  tem- 
perature the  year  round ;  so  that  the  hewers,  who  dig 
out  the  coal,  work  with  nothing  on  but  flannel  drawers. 
In  a  tin-mine  near  Redruth,  Cornwall,  at  a  depth  of 
eighteen  hundred  feet,  there  is  a  permanent  heat  of  one 
hundred  degrees,  which  is  that  of  one  of  our  very  hot 
summer-days.  The  miners,  it  is  said,  work  naked,  and 
ascend,  every  hour  or  so,  several  fathoms,  and  dip  them- 


20  LECTURES   ON   GEOLOGY. 

se/ves  in  pools  which  are  comparatively  cool,  to  enable 
them  to  labor  in  this  elevated  temperature.  In  the 
coldest  winter-day,  then,  we  are  less  than  half  a  mile 
from  the  warmest  summer-weather. 

Artesian  wells,  which  are  wells  bored  till  the  water 
flows  out,  instead  of  being  pumped  out,  reveal  in  like 
manner  the  earth's  interior  heat.  At  Grenelle,  near  Paris, 
is  an  artesian  well  nearly  eighteen  hundred  feet  deep. 
The  water  flowing  from  it,  at  the  rate  of  more  than 
five  hundred  gallons  a  minute,  has  a  heat  of  eighty-two 
•degrees,  being  an  increase  of  heat  from  the  stratum  of 
invariable  temperature  of  one  degree  for  every  fifty-nine 
feet ;  being  the  same  rate  of  increase  as  in  the  deep 
English  coal-mine.  At  Salzworth,  in  Germany,  is  an  arte- 
sian well  bored  for  salt  water  to  a  depth  of  2,144  feet, 
from  which  the  water  flows  at  a  heat  of  ninety-one 
degrees. 

A  remarkable  artesian  well  has  been  recently  bored 
at  Louisville,  Ky.,  to  the  depth  of  2,086  feet.  The 
water  rises  in  pipes,  by  its  own  pressure,  one  hundred 
and  seventy  feet  above  the  surface,  and  pours  out  at  the 
rate  of  two  hundred  and  thirty  gallons  a  minute.  As  it 
flows  from  the  top  of  the  well,  it  has  a  constant  tempera- 
ture of  seventy-six  and  a  half  degrees ;  but,  when  a 
registering  thermometer  was  sunk  to  the  bottom,  it 
indicated  a  heat  of  eighty-two  and  a  half  degrees,  or 
an  increase  of  one  degree  for  about  every  sixty-five  feet. 
If  the  heat  continues  to  increase  at  the  same  rate  with 
increased  depth,  as  there  is  every  reason  to  believe,  at  a 
depth  of  a  little  more  than  a  mile  and  a  half  we  should 
find  a  temperature  of  two  hundred  and  twelve  degrees, 
or  the  heat  of  boiling  water.  About  five  miles  down,  it 
must  be  hot  enough  to  melt  lead ;  twenty  miles  down, 


.     LECTURES   ON   GEOLOGY.  21 

hot  as  melted  gold  ;  and,  at  a  depth  of  forty  miles,  the 
heat  is  more  than  four  thousand  degrees  ;  and  there  are 
few  rocks  that  could  remain  solid  at  such  a  tremendous 
heat  as  this. 

The  crust  of  the  earth  has  been  variously  estimated 
at  from  ten  to  one  thousand  miles  in  thickness ;  but  it 
doubtless  differs  in  different  places.  The  immense  press- 
ure to  which  rocks  must  be  subjected  in  the  interior  of 
the  earth  may  cause  them  to  be  solid  at  greater  depths 
than  they  otherwise  could  be ;  but  it  is  not  probable 
that  the  crust  of  the  earth  is  anywhere  more  than  a 
hundred  miles  thick,  while  in  many  places  it  may  be 
not  more  than  twenty. 

It  may  be  considered  certain  that  we  stand  upon  a 
rocky  crust  resting  upon  a  fiery  ocean  ;  this  crust  bear- 
ing about  the  same  proportion  to  the  ocean  within  that 
the  shell  of  an  egg  bears  to  the  fluid  contents  of  that 
egg,  or  that  a  coat  of  ice  an  inch  thick  bears  to  a 
sixteen-feet-deep  lake  over  which  a  boy  may  be  skating. 
Ask  a  fly  what  he  thinks  of  an  egg,  and  he  says, "  It  is 
a  mountain  of  marble. "  When  you  hint  at  the  fluid  con- 
dition of  the  interior,  "  It  cannot  be  possible  !  Have  I 
not  walked  over  it,  climbed  its  mountains,  explored  its 
valleys,  and  stamped  upon  it  with  my  mighty  foot? 
Solid,  solid:  it  cannot  be  otherwise."  I  have  heard  men 
talk  in  the  same  way,  and  for  the  same  reason,  —  they 
knew  no  better.  Sir  John  Herschel  says,  "  The  central 
heat  of  the  earth  is  no  scientific  dream,  no  theoretical 
notion,  but  a  fact  established  by  direct  evidence  up  to 
a  certain  point,  and  standing  out  from  plain  facts  as  a 
matter  of  unavoidable  conclusion  in  a  hundred  ways." 
Prof.  James  D.  Dana  says,  "  The  fact  of  the  existence  of 
the  globe  at  one  time 'in  a  state  of  universal  fusion  is 
placed  beyond  reasonable  doubt." 


22  LECTURES   ON  GEOLOGY.     . 

We  know,  from  other  facts  that  I  shall  notice  by  and 
by,  that  the  earth  has  existed  for  millions  of  years, 
during  all  that  time  cooling,  and  its  crust  thickening  : 
hence  we  are  carried  back  to  a  time  in  its  history  when 
its  crust  was  very  thin ;  and  a  time  back  of  that,  when 
there  was  no  crust  upon  its  fluid  surface,  but  it  hung  in 
space  a  fiery  drop. 

A  second  reason  why  geologists  believe  in  the  original 
fluidity  of  the  earth  is  its  peculiar  shape.  We  say  the 
earth  is  round  ;  and,  as  we  generally  use  language,  this 
is  correct:  but  it  is  not  absolutely  correct;  for  the 
diameter  of  the  earth  from  pole  to  pole  is  about  twenty- 
six  and  a  half  miles  shorter  than  from  the  equator  to  the 
equator.  Why  should  it  be  so  ?  The  earth  revolves  on 
its  axis  so  rapidly,  that  a  body  on  its  equator  is  carried 
more  than  a  thousand  miles  an  hour.  It  is  well  known, 
that,  when  a  body  is  revolving  rapidly,  there  is  a  ten- 
dency in  the  matter  composing  it  to  fly  from  the  centre, 
by  virtue  of  what  is  called  centrifugal,  or  centre-flying, 
force.  We  see  this  force  operating  when  a  grindstone 
is  turning  quickly.  Let  water  be  poured  on  it,  and  the 
drops  fly  off  on  every  side  ;  and  sometimes  large  grind- 
stones thus  revolving  have  split  to  pieces,  so  strong 
was  the  tendency  of  the  particles  composing  them  to  fly 
from  the  centre.  There  is  the  same  tendency  in  the 
particles  of  matter  composing  the  earth  to  fly  from  its 
centre  as  it  rapidly  revolves.  Had  the  earth  been  abso- 
lutely solid,  they  could  not  have  obeyed  this  tendency  ; 
but  the  shape  of  the  earth  proves  that  they  have,  thus 
bulging  out  the  earth  at  the  equator :  hence  they  were 
'once  free  to  move,  or,  in  other  words,  in  a  fluid  condi- 
tion. This  could  not  have  been  from  the  water  compos- 
ing the  earth ;  for,  at  but  a  short  distance  below  the 


LECTURES   ON  GEOLOGY.  23 

surface,  it  is  too  hot  for  water  to  exist.  We  cannot 
avoid  the  conclusion,  then,  that  the  earth  was  once  a 
molten  globe,  and  its  motion  spun  it  into  its  present 
shape :  for  a  mathematician  can  take  the  mass  of  the 
earth,  its  size,  arid  the  rate  of  its  revolution,  and  calcu- 
late what  shape  its  centrifugal  force  would  give  it ;  and 
the  very  shape  that  it  should  be,  according  to  his  calcu- 
lations, is  the  identical  shape  it  possesses. 

Hot-springs  furnish  us  with  another  evidence  of  the 
internal  heat  of  the  globe,  and  give  us  reason  to  believe 
in  its  original  fluidity.  They  are  widely  distributed 
over  the  face  of  the  earth.  We  find  them  in  Greece, 
Italy,  Germany,  England,  on  the  slopes  of  the  Alps  and 
Andes,  in  numerous  islands  of  the  Pacific  Ocean ;  while 
Iceland  furnishes  boiling-fountains.  Nor  is  the  United 
States  destitute  of  them.  In  Virginia,  Arkansas,  Colo- 
rado, Utah,  and  California,  they  are  numerous ;  and  the 
water  in  some  of  them  has  a  heat  nearly  as  high  as  the 
boiling-point. 

Near  the  Sahwatch  River,  in  the  San-Louis  Valley, 
Col.,  there  is  a  boiling-spring  of  immense  size,  at  which 
hunters  sometimes  cook  their  provisions.  The  sound  of 
its  escaping  steam  can  be  heard,  as  I  was  informed,  at  a 
distance  of  a  mile  and  a  half. 

In  the  Middle  Park,  Col.,  I  examined  several  hot- 
springs  near  Grand  River,  having  a  temperature  of  from 
ninety-six  to  a  hundred  and  fourteen  degrees :  they  seem 
to  be  situated  along  the  line  of  a  crevice  caused  by 
upheaval.  At  Idaho,  ten  miles  from  Central  City,  in 
Colorado,  several  similar  hot-springs  exist,  which  appear 
also  to  be  on  a  crevice.  At  this  place  the  ground  was 
BO  hot.  that  miners  washing  for  gold  were  compelled,  in 
consequence  of  the  heat,  to  stop  digging  at  a  depth  of 


24  LECTURES   ON   GEOLOGY. 

twenty  feet.  Hot -springs  are  natural  artesian  wells 
made  by  crevices  going  down  to  immense  depths. 

The  geysers,  or  spouting  hot-springs  of  Iceland,  are 
probably  connected  with  the  volcanic  eruptions  to  which 
the  island  has  been  subjected ;  but  those  of  Sonoma 
County,  Cal.,  may,  I  think,  be  attributed  to  the  earth's 
interior  heat.  They  consist  of  a  number  of  boiling- 
springs  in  a  deep  ravine,  emitting  large  quantities  of 
steam  with  a  hissing  and  roaring  noise.  One  of  them, 
called  the  "  Steainpipe,"  sends  up  a  volume  of  steam 
more  than  a  hundred  feet  high. 

Iii  the  Colorado  Desert  are  boiling-springs  which  send 
up  fountains  of  water,  accompanied  with  steam,  to  a 
height  of  twenty  or  thirty  feet.  It  is  said  that  the 
escaping  steam  can  be  heard  at  a  distance  of  ten  miles. 

On  one  of  the  Feejee  Islands,  there  is  a  basin  forty 
feet  deep,  the  water  in  which  has  a  temperature  of  two 
hundred  and  ten  degrees  ;  the  natives  use  it  for  boiling 
their  food.  At  Baden,  in  Germany,  there  are  thirteen 
warm  springs:  one  of  them  pours  out  in  twenty-four 
hours  four  thousand  three  hundred  and  forty  cubic  feet 
of  water  at  one  hundred  and  fifty-three  degrees  of  heat. 

Sometimes  hot  and  cold  springs  are  found  side  by 
side.  Thus  Homer  says,  — 

"  Next  by  Scamander's  double  source  they  bound, 
Where  two  famed  fountains  burst  the  parted  ground: 
This,  hot,  through  scorching  clefts  is  seen  to  rise, 
With  exhalations  streaming  to  the  skies  ; 
That,  the  green  banks  in  summer's  heat  o'erflows, 
Like  crystal  clear,  and  cool  as  winter's  snows." 

One  of  these  springs  comparatively  shallow,  and  hence 
its  coolness ;  the  other  from  some  deep-seated  source 
receiving  its  continual  supply  of  heat. 


LECTURES   ON  GEOLOGY.  25 

Hot-springs  of  Greece,  referred  to  by  Herodotus,  are 
still  flowing,  though  we  know  that  more  than  two  thou- 
sand years  have  elasped  since  they  were  noticed  by  the 
historian.  If  a  woman  keeps  a  kettle  boiling  for  a  day, 
it  requires  considerable  fuel  to  do  it.  How,  then,  does 
Dame  Nature  keep  her  large  kettles  boiling  (some  of 
them  forty  feet  deep,  like  that  on  the  Feejee  Island), 
thousands  of  gallons  constantly  flowing  off,  and  this  sup- 
plied by  cold  water  to  be  heated,  and  that  not  for  a  day 
merety,  but  for  thousands  of  years  ?  The  heat  to  do 
this  evidently  comes  from  this  grand  reservoir  of  heat 
in  the  interior  of  the  earth,  which,  having  given  up  heat 
to  supply  the  numerous  hot-springs  of  the  immense 
geologic  periods,  must  have  been  at  one  time  much 
hotter  than  now;  and  we  can  readily  go  back  to  the 
time  when  the  whole  earth  was  so  intensely  heated,  that 
water,  could  not  rest  upon  its  surface. 

If  we  need  any  further  evidence  that  the  earth  was 
once  in  a  fluid  state,  volcanoes  supply  it.  Humboldt 
enumerates  two  hundred  and  twenty-five  active  volca- 
noes; that  is,  volcanoes  that  emit  vapors  at  the  present 
time,  or  have  had  eruptions  within  the  past  hundred  and 
fifty  years :  arid,  if  all  active  volcanoes  were  known, 
that  number  would  be  greatly  increased.  What  are 
these  volcanoes,  with  their  hollow  craters,  but  so  many 
chimneys,  communicating  with  this  grand  central  fire, 
from  which  escape  smoke,  ashes,  and  devouring  lava? 
They  are  found  from  Iceland,  in  the  frozen  north,  to 
Victoria  Land,  in  the  still  more  frozen  south ;  from  hills 
a  few  hundred  feet  high,  to  the  mighty  volcanoes  of 
South  America,  like  Cotopaxi  and  Antisana,  whose 
blazing  cressets,  nineteen  thousand  feet  above  the  sea- 
level,  have  been  seen  on  the  Pacific  Ocean  more  than  a 


26  LECTURES   ON  GEOLOGY. 

hundred  miles  from  the  coast.  Commencing  at  Chili  in 
South  America,  from  there  to  Equador,  volcanoes  are 
found  along  the  Andes  over  every  degree  of  latitude  : 
passing  in  a  line  through  Central  America  and  Mexico, 
and  along  the  Rocky-Mountain  chain,  they  cross  by  the 
Aleutian  Isles,  which  seem  like  so  many  stepping-stones 
from  the  new  continent  to  the  old,  and  contain  at  least 
thirty-four  active  volcanoes,  to  the  peninsula  of  Kam- 
tchatka ;  and  through  Japan,  and  connecting  volcanic 
vents  in  the  islands  of  the  Pacific  Ocean,  to  New 
Zealand;  forming  a  grand  volcanic  chain  twenty-six 
thousand  miles  in  length. 

The  phenomena  of  these  active  volcanoes  present 
the  strongest  evidence  of  the  present  internal  fluidity 
of  the  earth,  and  carry  us  back  by  fair  reasoning  to  the 
time  when  the  entire  globe  was  in  the  same  state  that 
its  interior  now  is. 

Vesuvius  is  a  name  familiar  to  every  one ;  for  who 
does  not  remember  the  first  geography  possessed  at 
school,  and  the  smoking-mountain  that  figured  in  it? 
Previous  to  the  year  79  A.D.,  Vesuvius  had  never  been 
seen  in  a  condition  of  activity;  or,  if  seen,  we  have  re- 
ceived no  account  of  it.  Pliny,  the  Roman  naturalist, 
does  not  include  Vesuvius  in  his  list  of  volcanoes; 
though  Strabo,  who  travelled  through  Italy  before  this 
time,  recognized  its  volcanic  character,  the  lava  and 
cinders  surrounding  it  revealing  its  true  nature  to  this 
keen  observer,  who  says  it  was  extinguished  for  want 
of  fuel.  A  spectator  in  the  summer  of  79  saw,  on  the 
coast  of  the  Bay  of  Naples,  two  beautiful  cities,  —  Her- 
culaneum  arid  Pompeii,  —  cities  occupied  by  a  remarka- 
bly intellectual  people.  Beautiful  villas  adorned  the 
neighboring  eminences,  occupied  by  the  Roman  nobility, 


LECTUEES   ON  GEOLOGY.  27 

who  came  to  spend  the  summer  months  in  what  is  even 
now  one  of  the  most  beautiful  spots  on  the  globe. 
Back  of  these  cities  towered  Mount  Vesuvius,  clad  with 
vine-yards  and  olive-yards,  and  crowned  with  a  belt  of 
chestnut-trees.  A  more  lovely  scene  of  beauty  never 
smiled  on  the  soul  of  an  artist.  The  streets  of  the  cities 
were  crowded  with  pedestrians,  the  stores  full  of  busy 
customers,  and  the  temples  attended  by  devout  wor- 
shippers. In  August  of  that  year,  the  people  were 
aroused  one  evening  to  a  sense  of  danger  by  low, 
rumbling  sounds  that  were  heard  beneath  their  feet,  as 
if  the  thunder  had  forsaken  the  heavens,  and  taken 
refuge  in  the  earth ;  and  this  followed  by  numerous 
earthquake-shocks.  The  next  day,  about  one  o'clock  in 
the  afternoon,  from  the  summit  of  the  mountain  rose  a 
dark  cloud,  to  which  all  eyes  were  turned.  It  had  the 
shape  of  a  pine-tree  when  first  seen,  but  gradually 
extended  until  it  darkened  the  sky,  and  a  purple  twi- 
light settled  down  upon  the  land  :  while  from  the  cloud 
fell  ashes  as  falls  the  snow  in  the  winter-time ;  and  out 
of  the  dim  dwellings  poured  the  distracted  multitudes 
into  the  narrow,  crowded  streets.  The  twilight  deep- 
ened till  a  darkness  of  more  than  midnight  enshrouded 
the  land,  —  a  terrible  darkness,  only  relieved  for  a 
moment  by  flashes  from  the  mountain,  that,  like  light- 
ning, pierced  the  gloom.  The  ground  rocked,  the  sea 
roared,  ashes  and  stones  fell  in  a  constant  shower ;  while 
the  terrified  inhabitants,  some  with  pillows  on  their 
heads,  fled  for  their  lives.  Down  came  the  ashes  for 
days :  foot  by  foot  they  rose,  till  house,  temple,  steeple, 
all  were  covered ;  and,  when  men  came  back  to  find 
their  old  homes,  there  was  nothing  to  be  seen  but  a 
desert  of  cinders,  dust;  and  ashes;  everywhere ;  and  no 


28  LECTURES   ON   GEOLOGY. 

spot  previously  known  could  be  recognized.  Its  ap- 
pearance before  and  after  the  eruption  is  thus  described 
by  Martial,  a  Latin  poet,  who  was  living  at  the  time, 
and  had  without  doubt  seen  it :  — 

"  Here  verdant  vines  o'erspread  Vesuvius'  sides ; 
The  generous  grape  here  poured  her  purple  tides ; 
This  Bacchus  loved  beyond  his  native  scene ; 
Here  dancing  satyrs  joyed  to  trip  the  green; 
Far  more  than  Sparta  this  in  Venus'  grace, 
And  great  Alcides  once  renowned  the  place : 
Now  flaming  embers  spread  dire  waste  around, 
And  gods  regret  that  gods  can  thus  confound." 

It  does  not  appear  that  any  lava  flowed  out  of  Vesu- 
vius at  this  time,  though  torrents  of  mud  were  poured 
out :  but  subsequently  lava  did  flow  over  the  spot  where 
Herculaneum  was  buried ;  and,  on  this  account,  exca- 
vation is  much  more  difficult  there  than  at  Pompeii. 

There  lay  the  cities,  deep  buried  ;  and  thus  they 
slept  for  sixteen  centuries  before  their  day  of  resurrec- 
tion came.  New  towns  were  built  on  the  sites  of  the 
old  ones,  the  people  little  dreaming  of  the  cities  that 
lay  beneath;  till  in  1713,  a  well  being  dug  above  Hercu- 
laneum, the  workmen  came  down  upon  the  old  theatre, 
where  the  statues  of  Hercules  and  Cleopatra  were 
found.  Pompeii  was  discovered,  forty  years  afterward, 
by  a  peasant  who  was  ploughing  in  his  vineyard.  Lying 
nearer  the  surface  than  Herculaneum,  and  only  covered 
with  ashes,  a  large  portion  has  been  exposed  to  daylight, 
to  the  great  joy  of  the  antiquarian. 

The  pavement,  composed  of  flags  of  lava,  was  found 
worn  by  the  chariot-wheels,  that  had  .been  so  long  still, 
to  a  depth  of  an  inch  and  a  half.  In  the  barracks,  the 
gcribblings  of  the  soldiers  in  their  idle  hours  upon  the 


LECTURES   ON   GEOLOGY.  29 

walls  were  distinctly  visible ;  while  in  the  stocks  were 
found  the  skeletons  of  two  of  them,  chained  wrist  to 
wrist.  Left  by  their  fellows,  unable  to  escape,  there 
they  sat  till  the  "fire-shower  of  ruin"  enveloped  them. 

Paintings  were  found  undimmed  by  the  touch  of  time; 
stores  just  as  they  were  left  by  their  owners,  articles 
lying  upon  the  counter.  "  I  noticed/7  says  M.  Simond, 
<l  in  the  Forum,  opposite  to  the  Temple  of  Jupiter,  a 
new  altar  of  white  marble,  exquisitely  beautiful,  and 
apparently  just  out  of  the  hands  of  the  sculptor.  An 
enclosure  was  building  all  round.  The  mortar,  just 
dashed  against  the  side  of  the  wall,  was  but  half  spread 
out!  You  saw  the  long,  sliding  stroke  of  the  trowel  about 
to  return  and  obliterate  its  own  track ;  but  it  never 
did  return;  the  hand  of  the  workman  was  suddenly 
arrested :  and,  after  the  lapse  of  eighteen  hundred  years, 
the  whole  looks  so  fresh  and  new,  that  you  would  almost 
swear  the  mason  was  only  gone  to  his  dinner,  and  about 
to  corne  back  immediately  and  smooth  the  roughness. 

"Proculus  was  a  rich  citizen;  and  his  house,  at  the 
time  of  the  eruption,  was  undergoing  repairs.  Painters' 
pots  and  workmen's  tools  were  found  scattered  round. 
On  a  bronze  dish,  a  sucking-pig  was  found  ready  for 
the  oven,  waiting  for  the  bread,  seventy  loaves  of 
which  were  found  in  the  oven,  turned  into  something 
like  coal. 

"A  sentinel  stood  at  the  door  in  his  box;  the  skeleton 
fingers  of  one  hand  holding  his  weapon,  and  the  other 
over  his  mouth. 

A  woman  staid  to  fill  her  apron  with  jewels,  but  fell 
in  the  open  court,  never  to  rise  again/7 

The  Temple  of  Isis  was  well  preserved.  The  skeleton 
of  a  priest  was  found  in  one  of  the  rooms,  and  near  his 


30  LECTURES   ON  GEOLOGY. 

remains  an  axe.  He  had  cut  his  way  through  two  doors, 
but  was  suffocated  before  the  third. 

In  the  eruption  that  destroyed  these  cities,  it  has 
been  calculated  that  twenty-two  million  cubic  yards  of 
matter  were  vomited  out  of  Vesuvius.  In  1737,  there 
was  another  eruption,  during  which  there  were  ejected 
twelve  million  cubic  yards;  and  in  1794  another,  in 
which  the  amount  of  matter  thrown  out  was  estimated 
at  twenty-two  million  cubic  yards.  Whence  this  im- 
mense amount  of  material?  The  mountain  evidently 
did  not  furnish  it;  neither  could  it  come  immediately 
from  beneath  the  mountain,  or  a  cavity  would  have  been 
formed,  into  which  the  weighty  mountain  would  have 
sunk.  It  doubtless  came  from  that  grand  ocean  of 
molten  matter,  as  truly  beneath  our  feet  to-day  as  it 
was  beneath  the  feet  of  the  inhabitants  of  Herculaneum 
and  Pompeii. 

There  have  been  several  recent  eruptions  of  Mount 
Vesuvius.  One,  which  took  place  in  1855,  is  thus 
described  by  a  correspondent  of  "  The  London  Athe- 
naeum : "  "  The  lava  was  pent  within  the  deep  banks 
of  a  wide  bed,  and  was  flowing  down,  not  like  a  fluid, 
which  is  the  ordinary  motion  of  it,  but  like  a  mountain 
of  coke,  or,  at  times,  like  highly  gaseous  coal.  It  split 
and  crackled  and  sparkled  and  smoked,  and  flamed  up, 
and  ever  moved  on  in  one  vast  compact  body.  Pieces 
detaching  themselves  rolled  down,  leaving  behind  a 
glare  so  fierce,  that  I  could  have  imagined  myself  at  the 
mouth  of  an  iron  furnace;  and  as  every  mass  fell  down 
with  the  noise  of  thunder,  or  rolled  sideways  from  the 
upper  surface  into  the  gardens  and  vineyards,  the  trees 
flamed  up,  and  the  crowds  uttered  shouts  of  admiration 
and  regret.  Following  the  course  of  the  stream,  or 


LECTURES   ON  GEOLOGY.  31 

rather  tracing  it  back  to  its  source,  we  walked  by  the 
side  of  that  huge  leviathan  through  highly-cultivated 
grounds,  now  trodden  under  the  feet  of  multitudes, 
until  we  arrived  at  the  edge  of  a  precipice ;  whence  we 
looked  into  the  boiling  flood,  fed  by  the  cascade  of  lava 
which  was  pouring  down  from  above.  Full  one  thou- 
sand feet  fell  that  glowing,  flaming  Niagara,  in  one 
unbroken  sheet,  over  the  precipice.  Forming,  at  first, 
two  cascades,  the  interval  between  had  been  filled  up 
by  the  immense  masses  of  scoriae  which  the  mountain 
had  thrown  out ;  and  now  it  majestically  rolled  down, 
one  continued  stream,  into  a  lake  of  boiling  fire.  There 
were-  times  when  projections  in  the  face  of  the  lava 
seemed  to  impede  its  course ;  then,  behind  those  pro- 
jections, accumulated  tons  upon  tons  of  material.  It 
was  a  moment  of  breathless  expectation :  all  eyes  were 
fixed  upon  that  one  blackened  spot.  There  was  a  slight 
movement ;  we  heard  a  click  ;  a  few  ashes  and  stones 
fell,  and  down  went  a  mountain  of  solid  fire  into  the 
boiling,  smoking  abyss,  with  the  noise  of  thunder." 

At  this  time,  Vesuvius  is  still  busy,  and  the  people 
in  its  vicinity  are  watching  the  progress  of  an  eruption 
with  intense  anxiety. 

^Etna,  nearly  eleven  thousand  feet  high,  is  one  of 
those  unruly  volcanoes  that  are  never  at  rest.  Virpl 
says,  — 

"  By  turns,  a  pitchy  cloud  she  rolls  on  high ; 
By  turns,  hot  embers  from  her  entrails  fly, 
And  flakes  of  mounting  flames  that  lick  the  sky. 
Oft  from  her  bowels  massive  rocks  are  thrown, 
And,  shivered  by  the  force,  come  piece-meal  down 
Oft  liquid  lakes  of  burning  sulphur  flow, 
Fed  from  the  fiery  springs  that  boil  below.'' 


32  LECTURES  ON  GEOLOGY. 

This  mountain,  ninety  miles  in  circumference,  com- 
posed as  it  is  of  beds  of  lava,  and  layers  of  ashes,  is  a 
grand  monument  of  the  igneous  activity  of  the  earth, 
and  bears  upon  its  sides  inscriptions  which  tell  of  the 
fluid  condition  of  its  interior. 

In  1669,  a  lava  current  ran  from  this  mountain,  and, 
after  overwhelming  fourteen  towns  and  villages,  arrived 
at  the  city  of  Catania.  The  people  of  the  city,  prepar- 
ing for  such  an  eruption,  had  built  walls  around  it,  for 
their  protection,  sixty  feet  high.  On  came  the  rocky 
torrent,  moving  less  than  a  mile  a  day,  but  with  irresisti- 
ble force ;  and,  reaching  the  wall,  it  rose  foot  by  foot 
to  the  top  of  the  rampart,  and  then  poured  into  the  city, 
ran  through  it,  and  beyond  it  into  the  sea,  in  a  stream  six 
hundred  yards  broad,  and  forty  feet  deep.  The  wall  of 
the  city  is  still  standing;  and  the  lava  stream,  hardened, 
of  course,  into  solid  rock,  may  now  be  seen  curling  over 
it.  The  lava  of  this  eruption  covered  eighty-foursquare 
miles. 

Lyell  says,  "  This  great  current  performed  the  first 
thirteen  miles  of  its  course  in  twenty  days,  or  at 
the  rate  of  one  hundred  and  sixty-two  feet  per  hour, 
but  required  twenty-three  days  for  the  last  two  miles  ; 
and  we  learn  from  Dolomieu  that  the  stream  moved, 
during  a  part  of  its  course,  at  the  rate  of  fifteen  hun- 
dred feet  an  hour,  and  in  others  it  took  several  days  to 
cover  a  few  yards.  While  moving  on,  its  surface  was,  in 
general,  a  mass  of  solid  rock ;  and  its  mode  of  advan- 
cing, as  is  usual  with  lava  streams,  was  by  the  occasional 
Gssuring  ( f  the  solid  walls.  A  gentleman  of  Catania, 
named  Pappalardo,  desiring  to  secure  the  city  from  the 
approach  of  the  threatening  torrent,  went  out  with  a 
party  of  fifty  men,  whom  he  had  dressed  in  skins  to  pro- 


LECTURES   ON   GEOLOGY.  33 

feet  them  from  the  heat,  and  armed  with  iron  crows  and 
hooks.  They  broke  open  one  of  the  solid  walls  which 
flanked  the  current  near  Belpasso,  and  immediately 
forth  issued  a  rivulet  of  melted  matter,  which  took  the 
direction  of  Paterno ;  but  the  inhabitants  of  that  town, 
being  alarmed  for  their  safety,  took  up  arms,  and  put  a 
stop  to  farther  operations." 

In  Iceland,  there  are  a  number  of  remarkable  volca- 
noes ;  none  more  so  than  Skapta  Jokul.  In  June,  1783r 
a  torrent  of  lava  flowed  from  this  mountain  with  a  loud, 
crashing  noise ;  filling  up  in  its  passage  a  deep  ravine 
which  the  River  Skapta  had  made,  which  was,  in  places, 
two.  hundred  feet  broad  and  six  hundred  feet  deep, 
and  then  the  bed  of  a  deep  lake.  One  week  after  this, 
out  burst  another  fiery  river,  rolling  rapidly  over  the 
surface  of  the  first,  then  farther,  damming  up  various 
streams,  and,  after  flowing  for  several  days,  filled  a  deep 
abyss  which  a  tremendous  cataract  had  been  hollowing 
for  ages,  and  again  continued  its  course ;  nor  did  it 
cease  to  flow  till  forty  miles  from  its  starting-place. 
This  stream  was  in  some  places  seven  miles  broad.  A 
few  weeks  afterward,  another  stream  flowed  in  an  oppo- 
site direction  for  fifty  miles  ;  its  greatest  breadth  being 
from  twelve  to  fifteen  miles.  It  has  been  calculated 
that  the  matter  poured  out  of  this  mountain  in  two 
months  would  make  a  solid  globe  six  miles  in  diameter. 
Thirteen  hundred  human  beings  lost  their  lives  by  this 
eruption,  which  also  destroyed  twenty  thousand  horses, 
seven  thousand  horned  cattle,  and  a  hundred  and  thirty 
thousand  sheep.  Iceland  has  not  yet  recovered  from 
its  terrible  effects. 

The  most  remarkable  of  recent  eruptions  is  that  of 
Tornboro,  a  volcano  on  Sumbawa,  one  of  the  Molucca 


34  LECTURES   ON   GEOLOGY. 

Islands,  in  April,  1815.  It  is  thus  described  in  the  his- 
tory of  Java  by  Sir  Stamford  Raffles :  — 

"  This  eruption  extended  perceptible  evidence  of  its- 
existence  over  the  whole  of  the  Molucca  Islands,  over 
Java,  a  considerable  portion  of  Celebes,  Sumatra,  and 
Borneo,  to  a  circumference  of  a  thousand  statute  miles 
from  its  centre,  by  tremulous  motions  and  the  report  of 
explosions ;  while  within  the  range  of  its  more  imme- 
diate activity,  embracing  a  space  of  three  hundred  miles 
around,  it  produced  the  most  astonishing  effects,  and 
excited  the  most  alarming  apprehensions.  In  Java,  at 
the  distance  of  three  hundred  miles,  it  seemed  to  be 
awfully  present.  The  sky  was  overcast  at  noonday 
with  clouds  of  ashes ;  the  sun  was  enveloped  in  an 
atmosphere  whose  palpable  density  he  was  unable  to 
penetrate ;  showers  of  ashes  covered  the  houses,  the 
streets,  and  the  fields,  to  the  depth  of  several  inches ; 
and,  arnid  this  darkness,  explosions  were  heard  at  inter 
vals  like  the  report  of  artillery  or  the  noise  of  distant 
thunder." 

At  Bima,  forty  miles  off,  the  roofs  of  houses  were 
crushed  by  the  weight  of  ashes  that  fell  on  them;  many 
of  them  being  rendered  uninhabitable.  The  sound  of 
the  explosions  was  heard  nine  hundred  and  seventy 
miles  off  in  one  direction,  and  seven  hundred  and 
twenty  miles  in  the  opposite  direction.  Out  of  a  popu- 
lation of  twelve  thousand,  in  the  province  of  Tomboro, 
only  twenty-six  escaped  with  their  lives.  It  has  been 
calculated  that  the  ashes  which  fell  on  this  occasion 
would  have  covered  the  whole  of  the  States  of  Maryland 
and  Delaware  to  the  depth  of  two  feet,  or  they  would 
have  made  a  mountain  twice  the  size  of  Mont  Blanc. 

On  Hawaii,  one  of  the  Sandwich  Islands,  is  an  active 


LECTURES   ON   GEOLOGY.  35 

volcano,  Kilauea.  Within  its  crater  is  a  lake  of  lava 
thirteen  hundred  feet  below  the  summit.  In  1840,  this 
lake,  fifteen  miles  in  circumference,  became  a  vast  boil- 
ing caldron  ;  the  lava  rising,  like  water  in  a  kettle,  till 
it  at  length  burst  through  the  side  of  the  crater,  and 
ran  for  forty  miles,  partly  underground,  and  partly  above 
ground ;  and  then  poured  into  the  sea,  for  three  weeks, 
"  in  a  blazing  cataract  as  wide  as  Niagara,"  heating  the 
water  of  the  ocean  for  twenty  miles  along  the  coast,  and* 
making  hills  of  scoria  and  sand  from  two  to  three  hun- 
dred feet  high.  Forty  miles  off,  the  finest  print  could 
be  read  at  midnight ;  arid  the  light  of  the  volcano  was 
like  that  of  the  rising  sun. 

Mauna  Loa  is  a  volcano  on  the  same  island,  thirteen 
thousand  feet  high.  In  1859,  a  terrific  eruption  took 
place,  described  by  various  observers.  On  the  evening 
of  Saturday,  Jan.  22,  the  snow  on  the  mountain  was 
seen  white,  and  there  were  no  signs  of  an  eruption  ; 
but  en  Sunday  thick  clouds  of  smoke  gathered  about 
the  mountain,  and  at  night  the  whole  sky  was  lit  up 
with  a  terrific  glare,  and  the  lava  could  be  seen  spout- 
ing in  a  jet  nearly  one  thousand  feet  high,  in  the  form 
of  an  immense  pyramid,  at  times  diverging  and  falling 
in  all  manner  of  shapes,  like  a  beautiful  fountain,  into 
a  crater  about  one  thousand  feet  in  diameter.  After 
flowing  eight  days,  a  stream  of  lava  reached  the  sea, 
where  it  spread  out  to  about  half  a  mile  in  width,  form- 
ing in  its  course  several  fiery  cascades  (one  of  which 
was  from  eighty  to  a  hundred  feet  high),  over  which 
the  lava  poured  in  a  stream  moving  at  the  rate  of  ten 
miles  an  hour. 

Mr.  Coan,  a  missionary  at  tjie  island,  thus  describes 
another  eruption  of  Mauna  Loa  as  recently  as  1866: 


36  LECTURES   ON   GEOLOGY. 

"  For  twenty  days  and  nights,  it  sent  up  a  fiery  jet  one 
hundred  feet  in  diameter,  varying  in  height  from  one 
hundred  to  a  thousand  feet.  As  it  issued  from  the 
awful  orifice,  it  was  at  a  white-heat  j  as  it  ascended 
higher  and  higher,  it  reddened  like  fresh  blood,  deepen- 
ing its  color,  until,  in  its  descent,  much  of  it  assumed 
the  appearance  of  clotted  gore.  From  this  fountain,  a 
river  of  fire  went  rushing  and  leaping  down  the  moun- 
tain with  amazing  velocit}r,  filling  up  basins  and  ravines, 
dashing  over  precipices  and  exploding  rocks,  until  it 
reached  the  forests  at  the  base  of  the  mountain,  where 
it  burned  its  fiery  way,  consuming  the  jungle,  evaporat- 
ing the  water  of  the  streams  and  pools,  cutting  down 
the  trees,  and  sending  up  clouds  of  smoke  and  steam, 
and  murky  columns  of  fleecy  wreaths,  to  heaven. 

"  All  Eastern  Hawaii  was  a  sheen  of  light,  and  our 
night  was  turned  into  day.  So  great  was  our  illumina- 
tion, that  one  could  read  without  a  lamp  ;  and  labor  and 
travel  and  recreation  went  on  as  in  the  daytime.  Mari- 
ners at  sea  saw  the  light  at  two  hundred  miles'  distance. 
The  rivers  of  fire  from  the  fountain  flowed  about  thirty- 
five  miles." 

What  immense  force  must  be  exercised  to  drive  the 
lava  from  the  interior  ocean,  perhaps  fifty  miles  deep, 
to  the  top  of  Mauna  Loa,  fourteen  thousand  feet  above 
the  sea-level !  The  distance  to  which  large  stones  are 
sometimes  thrown  impresses  us  likewise  with  the  exer- 
cise of  prodigious  force.  Cotopaxi  threw  a  stone,  one 
hundred  and  nine  cubic  yards  in  volume,  nine  miles. 

These  eruptions,  occurring  in  such  widely-separated 
portions  of  the  globe,  and  so  frequently,  are  strong 
evidences  of  the  fluid  character  of  its  interior. 

Extinct  or  dead  volcanoes  tell  the  same  story,  and 


LECTURES    ON   GEOLOGY.  37 

point  more  emphatically  to  the  original  fiery  condition 
of  the  whole.''  If  the  earth  was  once  a  fiery  fluid  mass, 
we  may  naturally  suppose  that  volcanoes  were  once 
larger  and  more  numerous  than  at  present ;  arid  this  is 
just  what  we  find.  The  Peak  of  Tenerifle,  twelve 
thousand  feet  high,  stands  in  the  centre  of  a  volcanic 
plain  containing  a  hundred  square  miles,  surrounded  by 
perpendicular  precipices  and  mountains,  which  were 
once  the  border  of  the  ancient  crater.  This  plain  was 
a  lake  of  boiling  rock,  dashing  its  fiery  waves  against 
those  precipitous  rocks  by  which  it  is  now  bounded. 

In  a  space  twenty  miles  long  and  ten  broad,  between 
Naples  and  Cumea,  in  Italy,  there  are  no  less  than  sixty 
craters,  some  of  them  larger  than  Vesuvius.  One  of 
them  is  two  miles  in  diameter.  The  city  of  Cumea  has 
stood  in  the  centre  of  one  for  three  thousand  years. 
Vesuvius  itself  is  merely  a  small  cone  erected  within 
the  crater  of  a  large  volcano. 

In  France,  extinct  volcanoes  and  their  products  cover 
thousands  of  square  miles.  They  exist  in  Spain  and 
Portugal,  Germany,  Asia  Minor,  Mexico,  and  the  Rocky- 
Mountain  region.  There  are  hundreds  in  the  Island  of 
New  Zealand  alone.  On  Hawaii  there  is  an  ancient 
crater  fifteen  miles  in  circumference,  and  another 
twenty  ;  while  in  Maui,  a  neighboring  island,  there  are 
two  others,  twenty-four  and  twenty-seven  miles  in  cir- 
cuit. From  these  facts,  we  are  naturally  led  back  to 
the  time  when  the  earth  was  one  grand  volcano,  with  no 
crater  to  confine  its  fiery  waves. 

Volcanoes  are  not  even  confined  to  the  land.  In  1831, 
a  volcano  burst  up  from  the  bottom  of  the  Mediterra- 
nean, off  the  coast  of  Sicily,  and  was  called  Graham's 
Inland.  One  month  after  its  appearance,  it  was  one 


38  LECTURES   ON   GEOLOGY. 

hundred  and  eighty  feet  high,  and  one  and  one-third 
miles  in  circumference.  It  disappeared,  however,  in  a 
few  years,  leaving  only  a  rocky  shoal. 

In  1811,  there  was  an  eruption  of  cinders  at  the  bot- 
tom of  the  sea  near  St.  Michael,  one  of  the  Azores. 
In  six  days,  an  island  was  formed  three  hundred  and 
twenty  feet  high.  It  was  the  third  time  that  an  island 
had  appeared  and  disappeared  near  the  same  spot. 

In  the  neighborhood  of  the  Aleutian  Isles,  in  1796,  an 
island  arose  from  the  sea,  which  continued  burning  for 
nearly  eight  years.  In  1819,  this  island  was  sixteen 
miles  in  circumference,  and  more  than  two  thousand 
feet  high.  As  I  write  this,  we  learn  from  "  The  London 
Times  "  that  a  new  Greek  island  has  just  risen  from  the 
bottom  of  the  Bay  of  Santorin.  The  bay  is  about  six 
miles  long  and  four  broad,  and  contains  three  islands 
that  have  risen  from  the  sea  during  the  historical  period. 
On  the  31st  of  January,  a  noise  was  heard  like  the  firing 
of  artillery  j  on  the  next  day,  flames  issued  from  the  sea 
to  the  height  of  fifteen  feet ;  on  the  4th  of  February, 
the  eruptions  were  more  violent,  gas  being  forced  up 
from  the  depths  with  terrific  noise  ;  next  morning,  the 
new  island  was  visible,  increasing  sensibly  to  the  eye, 
till  it  attained  the  height  of  a  hundred  and  thirty  feet, 
a  length  of  three  hundred  and  fifty,  and  a  breadth  of  a 
hundred  feet.  The  temperature  of  the  sea  in  the 
vicinity  rose  from  sixty-two  degrees  to  a  hundred  and 
twenty -two  degrees ;  which  is  hotter  than  the  hand  can 
bear. 

The  cooling  influence  of  water  for  untold  ages  has  not 
been  able  to  quench  the  internal  fires  of  the  globe ;  and 
we  are  ever  receiving  evidences  of  what  must  have 
been  the  condition  of  our  planet  when  heated  to  the 


LECTURES    ON  GEOLOGY.  39 

surface  over  its  whole  extent,  and  no  water  could  pos- 
sibly exist. 

Earthquakes  are  strong  evidences  of  the  present  fluid 
condition  of  the  earth's  interior.  If  the  earth  is  solid  to 
the  centre,  how  can  it  "  shiver  and  shake,  and  quiver 
and  quake/7  and  rise  and  fall  like  a  boat  on  a  stormy 
sea? 

At  Lima,  in  Peru,  there  are  on  an  average  forty-five 
earthquake-shocks  in  a  year.  In  Europe  and  adjacent 
parts,  observations  show  that  there  are  on  an  average 
about  forty  earthquakes  a  year ;  and  it  is  probable,  that, 
taking  the  whole  globe  into  account,  we  have  on  an 
average  an  earthquake  a  day. 

In  1692,  the  Island  of  Jamaica  was  visited  by  an 
earthquake,  which  caused  the  ground  "  to  swell  and 
heave  like  a  rolling  sea."  In  thousands  of  places,  the 
earth  opened  ;  and  plantations,  villages,  and  cities  sank 
to  rise  no  more.  A  tract  of  land  of  a  thousand  acres 
around  Port  Eoyal,  the  capital,  sank  down  in  less  than  a 
minute  during  the  first  shock ;  and  the  sea  immediately 
rolled  in.  A  frigate  that  was  repairing  at  the  wharf 
was  driven  over  the  tops  of  many  buildings,  and  then 
thrown  upon  one  of  the  roofs,  through  which  it  broke. 
Mountains  were  shattered ;  the  courses  of  rivers 
changed ;  new  lakes  were  formed,  and  old  ones  obliter- 
ated. 

In  1812,  the  Valley  of  the  Mississippi  was  terribly 
shaken  from  New  Madrid  to  the  mouth  of  the  Ohio 
River.  The  earth  was  raised  in  waves,  so  that  the  tree- 
tops  stooped  to  the  ground,  and,  as  the  wave  rolled  on, 
recovered  their  erect  position.  Lakes  were  formed 
several  miles  in  extent,  and  chasms  opened  in  the 
woods,  so  that  in  some  cases  men  chopped  down  trees, 


40  LECTURES   ON   GEOLOGY. 

and  sat  upon  them,  to  save  themselves  from  being  swal- 
lowed. When  these  convulsions  ceased  in  the  Missis- 
sippi Valley,  La  Guayra  and  Caraccas,  cities  in  South 
America,  two  thousand  miles  distant,  were  destroyed. 
The  violent  earthquake  of  Guadaloupe  in  1842,  which 
destroyed  several  towns  in  the  West-India  Islands,  ex- 
tended from  Charleston,  S.C.,  to  the  mouth  of  the  Ama- 
zon River.  The  earthquake-shocks  felt  in  Norway  are 
always  connected  with  volcanic  disturbances  in  Iceland. 

Humboldt  states  "  that  in  1797  the  volcano  of  Pasto, 
east  of  the  Guaytara  River,  emitted  uninterruptedly  for 
three  months  a  lofty  column  of  smoke ;  which  column 
disappeared  at  the  instant,  when,  at  a  distance  of  two 
hundred  and  eighty  miles,  the  great  earthquake  of  Rio- 
bamba,  and  an  immense  eruption  of  mud,  took  place, 
causing  the  death  of  between  thirty  thousand  and  forty 
thousand  persons."  On  the  nigh-t  in  which  Lima  and 
Callao  were  destroyed  by  an  earthquake,  four  new  vol- 
canoes broke  out  in  the  Andes. 

There  appears  to  be  a  subterranean  communication 
between  Vesuvius  and  ./Etna ;  so  that,  almost  invariably, 
when  one  is  active,  the  other  is  quiet.  The  communi- 
cation thus  found  to  exist  between  distant  volcanic 
vents  and  earthquakes  at  widely- separated  places 
points  to  the  great  interior  ocean  with  which  they  are 
connected. 

A  very  remarkable  earthquake  occurred  at  Lisbon  in 
1755.  It  was  the  1st  of  November,  —  All  Saints'  Pay. 
The  churches  were  crowded  with  worshippers,  when, 
about  nine  o'clock  in  the  morning,  they  were  startled 
by  that  subterranean  thunder  so  generally  accompany- 
ing earthquakes ;  and  in  a  moment  the  walls  crashed,  the 
steeples  toppled,  and,  in  six  minutes,  sixty  thousand 


LECTURES    ON   GEOLOGY.  41 

people  had  lost  their  lives,  —  thirty  thousand  killed  by 
falling  churches  alone:  for  an  earth-wave  passed  under 
the  city,  at  the  rate,  it  is  said,  of  twenty  miles  a  minute, 
though  accuracy  cannot  be  expected  in  calculations 
made  at  such  times ;  and  its  effects  were  felt  for  im- 
mense distances.  The  largest  mountains  of  Portugal 
were  split  and  shaken  from  their  very  foundations. 
Lead-miners  in  Derbyshire,  England,  heard  the  grinding 
rocks,  and  hurried  out  of  the  mines,  fearing  to  be 
enclosed  in  a  stony  prison  from  which  there  could  be 
no  release.  The  waters  of  a  hot-spring  at  Bath  sud- 
denly became  red,  and  hotter  than  usual.  In  the  Islands 
of  Antigua  and  Barbadoes,  in  the  West  Indies,  where 
the  tide  usually  rises  little  more  than  two  feet,  it  sud- 
denly rose  above  twenty  feet ;  and  the  water  became 
black  as  ink.  In  fact,  the  whole  bed  of  the  Atlantic 
seems  to  have  been  raised.  The  waters  of  Lake  Onta- 
rio were  observed  to  be  unusually  agitated.  At  Algiers, 
in  the  north  of  Africa,  the  earth  was  as  much  shaken  as 
in  Portugal;  and  a  town  in  its  neighborhood,  of  eight 
thousand  inhabitants,  was  swallowed.  "It  has  been 
computed,"  says  Ilumboldt,  "  that  a  portion  of  the 
earth's  surface  four  times  greater  than  that  of  Europe 
was  simultaneously  shaken."  Others  have  computed 
that  this  convulsion  sensibly  affected  one-twelfth  of 
ths  area  of  the  globe.  How  deep-seated  must  have 
been  the  cause  that  could  produce  so  wide-spread  an 
effect ! 

What  can  that  cause  be?  Taking  the  wing  of  a  dusky 
demon,  descend  with  me  into  the  nether  regions,  and  let 
us,  if  possible,  discover  what  it  is  that  shakes  the  earth 
BO  disastrously.  Through  soil,  sand,  and  gravel,  and  alter- 
nating strata  of  sandstone  and  limestone,  —  the  grave- 


42  LECTURES   ON  GEOLOGY. 

yards  of  unnumbered  generations,  —  we  descend  for 
thousands  of  feet.  Here  is  a  mineral  vein  :  by  it  we  can 
descend,  more  readily.  What  masses  of  lead,  in  sheets 
and  gigantic  cubes,  lining  immense  caves  !  But  we  can- 
not remain  long  to  admire  it.  Down  again,  through 
mica-schist,  gneiss,  granite,  and  quartz,  in  beds  of  im- 
mense thickness  ;  on  through  rocks  white  as  the  driven 
snow,  and  sparkling  as  that  snow  in  the  sunlight  of  a 
frosty  morning.  What  is  that  shining  substance?  How 
bright  and  beautiful !  It  is  gold,  —  a  lake  of  solid  gold  : 
once  fluid,  its  surging  waves  went  sweeping  along 
its  brilliant  surface,  but  now  still  as  a  "  painted  ocean." 
It  has  sunk  in  the  centre  as  it  cooled  ;  and  there  is  a 
grand  golden  amphitheatre  left,  a  mile  in  diameter. 
Down  again,  resolutely,  through  the  centre  of  this 
golden  floor.  Now  rocks  fly  past  us,  inky-black.  We 
are  diving  through  the  ribs  of  the  earth  to  its  warm 
heart ;  and  a  night  dark,  hot,  and  stifling,  closes  around 
us.  In  the  distance  we  behold  a  faint  gleam.  The  rocks 
are  cherry-red,  now  full  red  ;  and  now  they  glow  like 
the  walls  of  an  iron  furnace.  One  plunge,  and  we  stand 
on  the  shore  of  the  fiery  ocean,  and,  breathless  with 
terror,  look  upon  a  scene  such  as  mortal  eye  never 
before  beheld.  A  stillness  like  that  of  death  hangs  over 
it:  and  yet  it  does  move;  it  ebbs  and  flows  like  the 
ocean.  It  is  not  always  thus  calm.  At  times,  there  are 
dreadful  storms,  when  these  fiery  waves  roll  and  dash 
in  fury ;  and  a  storm  on  this  ocean  below  is  an  earthquake 
on  the  surface  above. 

But  what  could  make  a  storm  on  this  ocean  beneath? 
What  makes  a  storm  on  the  sea  ?  The  sun  rarefies  the 
air  over  one  portion  of  the  globe,  and  thus  makes  a 
partial  vacuum :  the  surrounding  air  rushes  in  to  fill  it, 


LECTURES   ON  GEOLOGY.  43 

and,  passing  over  the  water,  heaps  it  up,  and  rolls  it 
along  in  waves.  I  can  imagine  an  analogous  cause  at 
work  in  the  interior  of  the  earth.  Motion  and  heat  may 
be  constantly  transformed  into  electricity  within  the 
shell  of  the  earth  more  rapidly  than  it  can  be  conducted 
through  the  rocks  to  the  surface.  When  a  sufficient 
amount  has  thus  been  generated,  it  bursts  through  in 
some  weak  place  like  ^Etna  or  Vesuvius,  producing  vol- 
canic eruptions.  Thus  a  comparative  electric  vacuum 
is  produced  beneath  these  volcanic  vents  ;  and  the  elec- 
tricity in  other  portions  of  the  interior  ocean  propels  the 
fluid  mass  in  waves  toward  these  places,  these  waves 
lifting  the  rock  above  them  to  the  surface;  and  thus  an 
earth -wave  passes  along  that  surface,  corresponding 
with  the  wave  beneath,  and  producing  most  terrible 
effects. 

Some  attribute  volcanic  eruptions  to  the  contraction 
of  the  earth's  crust,  caused  by  its  cooling.  Thus  Lieut. 
Portlock  says,  "  The  solid  crust  continues  to  contract  as 
its  temperature  diminishes  in  a  greater  ratio  than  the 
central  mass  ;  and,  as  the  velocity  of  rotation  must 
increase  as  the  diameter  of  the  planet  diminishes,  there 
will  be  a  tendency  to  diverge  farther  from  the  spherical 
form,  and  hence  the  fluid  matter  within  will  press 
against  the  contracting  crust,  and  produce  volcanic 
eruptions.  M.  Cordier  has  calculated  that  a  contraction 
of  -joj^g-  of  an  inch  in  the  mean  radius  of  the  earth 
would  be  sufficient  to  force  out  the  matter  of  a  volcanic 
eruption." 

Earth-shakings,  and  some  destructive  ones,  may  have 
been  produced  in  this  manner.  Between  the  fiery  ocean 
and  the  rocky  shell  that  encloses  it,  there  probably  are  in 
place?  vast  arched  spaces,  against  whose  sides  the  lava 


44  LECTURES   ON  GEOLOGY. 

waves  beat  at  times,  and  deposit  rock.  This  arch  giving 
way  by  the  contraction  of  the  earth's  crust,  overhanging 
masses,  weighing  millions  of  tons,  drop  into  the  ocean 
beneath,  and  produce  a  wave,  which,  rolling  to  where 
roof  and  ocean  are  in  direct  contact,  uplifts  the  rocks  to 
the  surface ;  and  we  have,  consequently,  an  earthquake- 
wave,  most  violent  nearest  the  place  of  disturbance,  and 
dying  away  as  the  waves  of  the  underground  ocean  sink 
into  a  calm. 

Small  earthquake-shocks  are  often  produced  by  masses 
of  rock  falling  into  subterranean  cavities:  some  of  these 
may  be  heard  and  felt  for  great  distances.  The  motion 
of  a  passing  locomotive  can  be  distinctly  felt  in  some 
houses  a  mile  from  the  railroad. 

It  has  been  proved  by  long  and  careful  observation 
of  earthquake-shocks,  that  the  number  near  new  and  full 
moon  exceeds  the  number  at  the  quarters,  nearly  in  the 
proportion  of  six  to  five;  and  their  frequency  increases 
when  the  moon  is  nearest  to  the  earth  :  that  is,  when  the 
tides  of  the  ocean  are  highest,  earthquakes  are  most 
numerous  ;  the  influence  of  the  sun  and  moon  upon  the 
internal  ocean  being  still  felt  and  indicated. 

I  have  dwelt  longer  on  this  portion  of  my  subject  than 
some  might  deem  necessary,  because  there  are  many 
facts  presented  to  us  in  the  study  of  geology  that  can 
only  be  accounted  for  by  a  knowledge  of  the  original 
igneous  or  fiery  condition  of  the  earth,  and  its  gradual 
cooling  during  long  ages.  This  explains  why  the  lowest 
rocks  are  fire-made,  why  they  contain  no  remains  of 
animals  or  vegetables,  why  the  climate  of  Great  Britain 
was  once  as  hot  as  that  of  Cuba,  and  why  the  remains  of 
tropical  trees  are  found  in  Central  Vermont ;  how  corals 
existed  as  far  north  as  Baffin's  Bay,  and  why  the  earliest 


LECTURES   ON  GEOLOGY.  45 

rocks  formed  by  water  have  been  changed  into  crystalline 
rocks :  in  short,  destitute  of  this,  we  have  no  certain 
geological  guide,  and  facts  are  continually  presenting 
themselves  that  we  have  no  means  of  explaining. 

But  what  could  have  produced  this  iutensely  heated 
condition  of  the  earth  ?  It  is  not  positively  known  ;  and 
yet  astronomers  and  geologists  are  generally  agreed  as 
to  the  way  in  which  they  think  it  was  produced.  Facts 
discovered  by  astronomers  during  long  periods  of  obser- 
vation have  led  to  the  formation  of  a  theory  which 
accounts  most  beautifully  for  the  original  fiery  condition 
of  the  earth. 

Most  persons  are  sufficiently  acquainted  with  astrono- 
my to  know  that  the  earth  belongs  to  what  is  called  the 
solar  system.  In  this  system,  the  sun  is  the  grand 
centre,  around  which  a  number  of  bodies  are  revolving, 
known  by  the  name  of  planets.  First,  Mercury,  or,  as  far 
as  we  positively  know,  the  first,  at  a  distance  of,  in 
round  numbers,  thirty-five  millions  of  miles  from  the 
sun  ;  thirty-one  millions  of  miles  farther  into  space  is 
Venus ;  and  twenty-six  millions  farther,  our  own  planet. 
First  outside  of  the  earth's  orbit  is  Mars ;  then  a  number 
of  small  planets,  of  which  we  know  about  ninety,  and 
perhaps,  if  we  knew  them  all,  we  might  count  more 
than  ninety  thousand  ;  then  Jupiter,  Saturn,  Uranus,  and 
Neptune,  believed  to  be  the  outermost  planet  of  the 
solar  system,  at  the  enormous  distance  of  nearly  three 
thousand  millions  of  miles  from  the  SUL. 

There  are  some  remarkable  facts  known  in  reference 
to  these  bodies.  First,  they  are  all  round  or  globular 
bodies.  The  Sun,  Mercury,.  Venus,  the  Earth,  Mars,  and 
all  the  rest,  are  globes.  Why  should  this  be  so?  Why 
not  triangles  or  cubes  or  pentagons  ?  Or,  if  round,  why 


48  LECTURES   ON  GEOLOGY. 

not  round  like  a  cylinder,  a  table,  a  top,  or  a  sugar-loaf? 
Or  why  not  one  round,  another  square,  and  a  third  flat  ? 
We'  see  a  resemblance  among  them,  which  becomes  mo~e 
apparent  when  we  are  better  acquainted  with  them. 

Not  only  are  they  all  globes,  but  they  are  all  in  motion, 
and  moving  in  one  direction,  and  nearly  in  one  plane. 
The  sun  does  not  move  around  the  earth,  as  the  ancients 
supposed  that  it  did ;  but  it  does  revolve  upon  its  axis 
from  west  to  east.  In  the  same  direction,  Mercury  trav- 
els around  the  sun ;  so  Venus,  so  the  Earth,  and  all  the 
primary  planets.  These  bodies,  we  see,  are  no  longer 
lone  wanderers  in  space,  that  chance  has  scattered 
abroad :  they  are  members  of  one  grand  family,  bearing 
so  great  a  resemblance  to  each  other,  that  we  at  once 
suspect  that  they  must  have  had  a  common  origin. 

Another  remarkable  fact  connected  with  the  planets 
revolving  around  the  sun,  and  the  satellites,  or  moons, 
that  revolve  around  them,  is,  that  their  periods  of  revolu- 
tion are  increased  in  proportion  to  their  distance  from 
the  bodies  around  which  they  revolve.  Thus  Mercury 
travels  around  the  sun  in  88  days,  Venus  in  224  days, 
the  Earth  in  365  days,  Mars  in  686  days,  Ceres  in  4 
years  and  9  months,  Jupiter  in  12  years,  Saturn  in  29£ 
years,  Uranus  in  82  years,  and  Neptune  in  about  164 
years.  So  that,  if  Neptune  is  blessed  with  seasons,  it 
has  41  years  of  spring,  41  of  summer,  41  of  fall,  and  41 
of  winter.  I  pity  the  child  born  on  that  planet  about 
the  end  of  the  fall,  with  a  forty-one-years'  winter  ahead 
of  him,  especially  such  a  winter  as  Neptune's  must  be. 
Should  he  live  to  be  one  year  old,  he  would  be  considered 
a  marvel  of  old  age  in  this  faster-going  planet  of  ours. 

Saturn's  first  or  nearest  satellite  performs  its  revolu- 
tion around  it  in  22 £  hours,  the  second  in  1J  days,  the 


LECTURES   ON  GEOLOGY.  47 

third  in  2  days,  the  fourth  in  2|-  days,  the  fifth  in  4J 
days,  the  sixth  in  1G  days,  the  seventh  in  22  days,  and 
the  eighth  in  79  days.  Jupiter's  first  satellite  revolves 
around  it  in  42  hours,  the  second  in  3  J  days,  the  third  in 
7  days,  and  the  fourth  in  16|  days. 

One  more  important  fact  has  been  observed,  —  the  sun 
and  all  the  primary  planets  that  have  satellites  accompany- 
ing them  rotate  upon  their  axes  in  less  time  than  the 
planets  or  satellites  revolve  around  them.  Thus  the  sun 
revolves  upon  its  axis  in  25|-  days,  —  a  much  shorter  time 
than  that  of  the  revolution  of  any  planet  around  it ;  the 
earth  revolves  upon  its  axis  in  one  day ;  while  the  moon 
requires  more  than  27  days  to  describe  a  revolution 
around  the  earth.  Jupiter  revolves  upon  its  axis  in  10 
hours,  while  its  nearest  satellite  revolves  around  it  in  42 

hours.     Saturn's  time  of  rotation  is  10 J-  hours,  while  its 

&  / 

nearest  satellite  requires  22*-  hours  to- revolve  around  it. 
These  facts,  and  others  of  less  importance,  have  led  phi- 
losophers to  inquire  for  a  cause  adequate  to  account  for 
them;  and  thus  the  Nebular  Theory  had  its  origin. 

According  to  this  theory,  there  was  a  time  in  the 
almost  infinite  past,  when  all  the  matter  now  contained 
in  the  sun,  the  various  bodies  of  the  solar  system,  and 
the  stars,  existed  as  nebulous  or  gaseous  matter,  intensely 
heated,  and  exceedingly  rare.  In  this,  as  it  cooled, 
centres  of  aggregation  were  formed,  toward  which  flowed 
the  nebulous  matter ;  producing  by  that  flow  rotary 
motion  in  the  aggregated  centres  or  immense  suns  thus 
formed.  In  this  way,  the  grand  centre  of  our  solar 
system  was  produced,  occupying  all  the  space  now 
occupied  by  the  planets,  and  much  more,  —  a  globe,  prob- 
ably, a  hundred  thousand  million  of  miles  in  diameter, 
and  in  an  exceedingly  heated  condition.  This  stupen- 


48  LECTURES   ON   GEOLOGY. 

dous  globe  was  in  motion  from  west  to  east,  and  radi- 
ating its  heat  into  space,  which  is  known  to  be  more 
than  two  hundred  degrees  below  zero.  As  its  heat 
decreased,  it  necessarily  became  smaller,  cooling  bodies, 
as  a  rule,  contracting  in  size ;  and,  becoming  smaller, 
moved  with  greater  velocity,  on  the  same  principle  that 
a  stone  fastened  to  a  string,  and  whirled  around  the 
finger,  flies  with  more  velocity  as  the  string  winda 
around  the  finger  and  becomes  shorter.  But,  as  the 
velocity  increased,  the  centrifugal  force  heaped  up  the 
matter  around  the  equator  of  the  revolving  sun,  and 
caused  it  eventually  to  separate  from  the  main  body  in 
the  shape  of  a  zone,  or  ring.  By  experiment  it  has 
been  proved  that  a  drop  of  oil  floating  in  alcohol  will 
do  this  when  revolving  with  sufficient  rapidity.  The 
matter  composing  this  ring,  on  breaking  up,  which, 
unless  exactly  balanced,  it  would  be  sure  to  do,  flowed 
into  a  globe  by  virtue  of  the  attraction  of  gravitation ; 
the  same  law  that  rounds  a  dewdrop  on  a  grassy  spear 
sphering  the  worlds  in  space  :  for  these  grand  laws  know 
no  great  and  no  small,  — just  as  ready  to  round  a  world 
as  to  round  a  rain-drop. 

Thus  we  may  suppose  Neptune  was  launched  into 
space ;  at  first  a  nebulous  ring,  and  finally  a  rotating 
globe  or  planet,  the  first-born  of  the  Sun ;  it,  in  turn, 
becoming  the  parent  of  smaller  globes  or  moons.  Thus, 
also,  Uranus  and  her  moons ;  Saturn  with  a  family  of 
eight  satellites  and  rings,  so  nicely  balanced,  that  they 
have  been  preserved,  which,  by  their  very  exceptional 
appearance,  favor  this  theory  of  their  origin ;  and, 
lastly,  the  Earth,  with  her  solitary  child  the  Moon,  the 
last  fertile  planet  of  the  solar  system. 

How  beautifully  this  theory  accounts  for  the  facts  of 


LECTURES  ON    GEOLOGY.  49 

the  solar  system  that  have  claimed  our  attention  !  Why 
are  the  planets  round  or  globular  bodies  ?  Because 
they  were  originally  fluid ;  and  the  law  of  gravitation 
rounded  them  in  the  same  way  that  it  spheres  a  tear- 
drop as  it  falls  from  the  eye.  Why  are  the  planets 
moving  bodies?  why  do  they  all  move  in  the  same 
direction,  and  nearly  in  the  same  plane  ?  and  why  is  that 
plane  nearly  coincident  with  the  sun's  equator?  The 
sun  moving  from  west  to  east  originally,  as  it  now 
does,  communicated  its  motion  to  the  successive  rings 
that  were  separated  from  it;  and,  as  they  were  separated 
from  the  sun's  equator,  they  still  remain  in  about  the 
same  plane.  We  see,  too,  why  the  outermost  planets  and 
satellites  take  the  longest  time  to  perform  their  revolu- 
tions. When  Neptune  was  separated  from  the  sun,  the 
sun  was  of  immense  size,  and  moved  slowly;  but  as  it 
became  smaller,  and  moved  more  rapidly,  every  planet 
partook  in  regular  order  of  this  increased  rapidity  of 
motion:  and  thus  Mercury  travels  round  more  rapidly 
than  any  other  planet ;  and,  for  the  same  reason,  the 
nearest  satellite  of  any  planet  is  the  most  rapid,  and  the 
sun  and  planets  more  rapid  in  their  revolutions  than  any 
body  revolving  around  them. 

The  present  condition  of  some  of  the  nebulte  seen  in 
the  heavens,  which  cannot  be  resolved  into  stars  by  the 
best  telescopes,  indicates  the  existence  of  systems  in 
that  nebulous  condition  from  which  this  theory  supposes 
our  solar  system  originally  came.  Nay,  recent  spectrum 
analysis  has  demonstrated  the  gaseous  condition  of  some 
of  the  nebulas ;  while  it  shows  that  the  sun  is  in  such  a 
heated  condition,  that  iron,  copper,  zinc,  and  other  metals, 
exist  in  its  atmosphere  in  the  condition  of  vapor ;  while 
the  telescopic  appearance  of  the  moon,  with  its  mighty 


50  LECTUEES   ON  GEOLOGY. 

craters,  its  lava-streams,  and  marks  of  igneous  action 
nearly  everywhere,  indicates  an  original  fiery  condition 
for  it,  such  as  we  have  proved  to  have  been  the  state  of 
the  earth  at  an  early  time,  and  such  as  is  demanded  by 
this  theory. 

The  Nebular  Theory  was  first  suggested  by  the  elder 
Horschel,  was  elaborately  developed  by  La  Place  the 
great  French  astronomer,  and  has  received  the  support 
of  the  best  scientific  minds  that  have  investigated 
it.  Mitchell,  the  Cincinnati  astronomer  and  lamented 
patriot,  says  in  reference  to  it,  "  Such  is  a  brief  outline 
of  one  of  the  most  sublime  speculations  that  ever  re- 
sulted from  the  efforts  of  human  thought.'7  Dr.  Mantel], 
an  English  geologist,  says,-  "  This  theory  of  the  conden- 
sation of  nebulous  matter  into  suns  and  worlds,  marvel- 
lous as  it  may  appear,  will  be  found  on  due  reflection  to 
suggest  the  only  rational  explanation  of  the  phenomena 
observable  in  the  sidereal  heavens  and  in  our  own  globe, 
according  to  the  present  state  of  the  physical  sciences." 
Dr.  Buckland,  in  his  Bridgewater  treatise,  remarks,  "  The 
Nebular  Hypothesis  offers  the  most  simple,  and  therefore 
the  most  probable,  theory,  respecting  the  first  condition 
of  the  material  elements  that  compose  our  solar  system." 
Dr.  Pye  Smith  says,  "  The  Nebular  Hypothesis,  ridiculed 
as  it  has  been  by  persons  whose  ignorance  cannot  excuse 
their  presumption,  is  regarded  by  some  of  the  finest  and 
most  Christian  minds  as  in  the  highest  degree  probable." 
Lastly,  Humboldt,  the  noblest  name  of  which  science  can 
boast,  says  in  his  "  Cosmos,"  "  In  the  first  formation  of 
the  planets,  it  is  probable  that  nebulous  rings  revolving 
around  the  sun  were  agglomerated  into  spheroids,  and 
consolidated  by  a  gradual  condensation  proceeding  from 
the  exterior  towards  the  centre." 


LECTURES  ON  GEOLOGY.  51 

Behold  the  earth,  then  !  — 

"  It  goes  its  glorious  course  to  run, 
A  fire-globe  whirled  from  the  burning  sun." 

Uproll  the  curtain  that  unnumbered  ages  have  dropped, 
and  view  the  wondrous  scene.  Before  us  spreads  a 
fiery  ocean,  bounded  only  by  a  fiery  sky :  its  lightning- 
capped  billows  heave  heavily  under  the  influence  of  sun 
and  moon ;  and  now,  as  if  mad,  they  leap  in  fury  to  the 
ruddy  clouds  that  lower  above  them.  Hissing,  seething, 
boiling  like  a  huge  caldron,  while  dense  vapors  rise  con- 
tinually from  its  agitated  surface,  it  presents  to  us  a 
picture  that  none  but  a  demon  could  truly  paint.  Its 
air,  if  air  it  may  be  called,  is  hotter  than  the  volcano's 
breath,  and  more  deadly  than  the  dread  simoom.  There 
is  no  night,  with  grateful  shade  and  cooling  dews ;  no 
winter,  whose  piercing  winds  may  assuage  this  terrific 
heat :  there  is  but  one  unvarying,  fiery  day ;  one  inter- 
minable, burning  year.  Surrounded  by  an  atmosphere 
whose  bulk  is  vastly  greater  than  that  of  the  earth 
itself,  it  looks  more  like  a  blazing  comet  than  a  world 
destined  to  be  the  peaceful  abode  of  human  beings. 

In  this  state  of  the  earth,  all  the  metals,  in  conse- 
quence of  the  intense  heat,  must  have  existed  in  the 
atmosphere  in  the  condition  of  vapor;  and,  as  it  cooled, 
they  dropped  upon  its  surface  in  showers, —  gold,  silver, 
copper,  iron,  lead,  tin,  and  quicksilver,  —  lakes  of  these, 
rivers  of  these,  rising  in  vapor,  forming  clouds,  and 
condensing  over  and  over  again  ages  before  any  water 
existed  on  the  globe.  Where  was  the  water  during  this 
period  ?  All  the  water  now  contained  in  rivers,  lakes 
seas,  and  a  component  part  of  rocks,  was  then  in  the 
atmosphere.  "  But  the  atmosphere  is  not  large  enough 
to  hold  it,'7  replies  an  objector.  True,  it  is  not  now,  but 
amply  sufficient  then.  The  oxygen  of  the  globe  (half  of 


52  LECTURES   ON    GEOLOGY. 

the  earth's  known  crust  being  composed  of  it)  was  then 
in  the  atmosphere ;  all  the  carbon  now  locked  up  in  the 
coal-beds  (coal  containing  from  fifty  to  ninety  per  cent 
of  it)  must  have  been  there  also  as  gas ;  the  carbon  in 
limestone  was  also  there  (it  composes  one-eighth  of  all 
limestone  rocks) ;  united  with  oxygen,  in  the  form  of  car- 
bonic-acid gas,  every  cubic  yard  contains  seventeen 
thousand  cubic  feet.  What  a  volume  in  the  thousands 
of  cubic  miles  of  limestone  !  and  what  an  immense  at- 
mosphere there  must  have  been  before  the  consolidation 
of  so  large  a  part  of  it  into  rock !  Thus  the  vapor  of 
all  the  water  in  the  world  could  be  easily  contained  in  it. 

It  is  exceedingly  difficult  to  obtain  a  correct  idea  of 
the  condition  of  the  earth  during  this  time,  —  age  after 
age,  heat  radiating  into  cold  space ;  rock  forming  on 
the  surface  of  the  shoreless,  fiery  sea,  as  forms  the  ice 
on  a  lake  ;  forming  and  breaking  and  re-forming,  only  to 
rend  again,  as  the  red  billows  sweep  beneath,  to  unite  in 
firmer  bands  than  before.  Sluggish  waves  incessantly 
roll  round  and  round  the  globe  ;  and  these,  breaking,  and 
heaping  up  the  black  sheets  of  rocks  as  they  form  upon 
the  surface,  produce  craggy  islands,  against  whose  banks 
the  waves  dash,  and  congeal  into  rock.  Islands  thus 
formed  unite  into  continents,  and  at  length  cover  the 
earth's  face,  and  hide  its  glory :  it  ceases  to  shine  in  the 
heavens  a  star,  and  must  henceforth  be  indebted  to 
other  bodies  for  its  light,  and  eventually  for  heat. 

Let  the  earth  be  gradually  heated  until  it  assumes  the 
condition  of  vapor.  Not  long,  and  the  tropical  regions 
would  be  uninhabitable  by  man,  and  there  would  be  a 
general  migration  to  the  north.  The  ice  would  melt  from 
Greenland  and  the  north  and  south  polar  regions,  and 
ere  long  they  would  abound  with  living  beings  now  only 


LECTURES  ON  GEOLOGY.  53 

found  in  temperate  climes.  The  whale,  seal,  walrus,  and 
white  bear,  would  make  their  way  to  the  poles ;  and  the 
Esquimaux  would  follow  them.  The  heat  would  become 
so  great  eventually,  that,  in  the  temperate  regions,  the 
sheep,  the  ox,  and  the  deer  could  no  longer  exist :  one  by 
one  they  would  perish  as  an  extra  tropical  climate  spread 
over  the  whole  earth.  The  heat  increasing,  man  dies, 
and  the  beasts  generally  perish;  those  living  in  trees  and 
in  extreme  northern  regions  remaining  longest.  Then 
the  birds  die  :  but  insects  and  reptiles  swarm  in  increased 
numbers  the  world  over ;  but,  the  heat  continuing  to  in- 
crease, they  at  length  also  die.  The  plants  of  the  tem- 
perate regions  are  all  gone,  and  even  the  tropical  plants 
at  last ;  and  a  desert  world  is  here.  The  water  still  abounds 
with  fish,  and  sea-weeds  flourish  in  a  myriad  forms  ;  but 
these  at  length  expire.  Infusoria  exist  till  the  water  is 
boiling  hot ;  but  at  length  they  cease  to  exist,  and  all  life 
is  gone.  In  time,  all  the  water  is  turned  into  steam. 
The  heat  continues,  and  the  oil  in  the  earth  is  made  to 
boil :  in  some  places  it  takes  fire  and  burns,  and  in  others 
is  driven  off  in  vapor.  The  coal  burns  at  length,  and  its 
carbon  is  transformed  into  carbonic-acid  gas.  The  lime- 
stone of  the  world  is  burned  into  lime;  the  metals  melt; 
quicksilver  rises  in  vapor,  then  lead,  copper,  iron,  and 
gold ;  the  mountains  sink  and  dissolve ;  and,  as  the  heat 
increases,  the  rocks  themselves  are  resolved  into  gases 
and  vapor,  and  ascend  :  the  world  has  become  a  mass  of 
molten  matter,  belted  by  an  enormous  atmosphere  ;  and 
we  have  at  last  an  unseparated  nebulous  mass,  like  that 
from  which  all  we  behold  has  been  produced. 

Some  faint  conception  of  the  time  consumed  in  form- 
ing a  foundation  for  the  continents  to  be  built  upon  may 
bo  obtained  by  considering  the  following  facts:  Lava 


54  LECTURES   ON   GEOLOGY. 

from  Mount  JEtna,  in  1819,  moved  down  a  considerable 
slope,  at  the  rate  of  a  yard  an  hour,  nine  months  after  its 
emission  ;  and  in  the  crevices  of  the  mass  a  dull-red 
heat  could  be  seen  by  night,  and  vapor  rising  from  them 
was  visible  by  day.  Lava  from  the  same  mountain  at  a 
previous  eruption  was  in  slow  motion  ten  years  after- 
ward. A  mass  of  lava  sixteen  hundred  feet  thick  was 
ejected  from  Jorullo,  in  Mexico;  and,  though  a  hundred 
years  have  passed,  it  is  not  cool  yet :  travellers  push 
their  walking-sticks  into  the  crevices ;  and  the  heat  is 
still  intense  enough  to  char  the  ends  of  them.  How 
long  must  it  have  taken  the  earth  to  cool  sufficiently  to 
allow  a  rocky  crust  to  rest  upon  its  surface  !  Count  ten 
thousand  years  for  every  hair  of  your  head,  and  you 
have  by  no  means  over-estimated  the  time  necessary. 
Yet  it  came ;  for  Nature  commands  eternity,  and  she  is 
never  niggardly  of  time.  Now  is  the  floor  of  the  world 
laid  down,  black,  hard,  bare  as  the  pavement  of  the 
street,  hot  as  an  oven  :  it  stretches  away,  a  craggy  des- 
ert of  desolation  surrounding  the  globe;  its  monotony 
broken  only  by  the  numerous  volcanic  mouths  that  pour 
out  lava-floods  continually. 

The  time  comes  when  this  is  cool  enough  to  allow  the 
water  to  condense  upon  it ;  and,  as  it  falls  in  drops,  it 
is  speedily  dissipated  in  steam,  rising  in  dense  clouds 
to  the  heavy  atmosphere.  This  cooled  the  earth's  sur- 
face more  rapidly  than  before ;  and  at  length  the  water 
remained  in  the  hollows.  The  oceans  were  born,  boiling, 
dark,  heavy,  and  impure,  arnid  heaving^,  roarings,  flash- 
ings, and  terrible  storms  and  convulsions.  There  stretch- 
es a  chasm  miles  away ;  and  between  the  dark,  craggy 
walls  that  bound  it,  see  the  boiling  lava,  like  a  river  of 
melted  gold,  rolling  its  waves  along  !  Now  water  flows 


LECTURES   ON  GEOLOGY.  55 

into  it :  the  ground  moves  beneath  our  feet.  What  an 
explosion  !  All  the  gunpowder  of  the  world  fired  at  one 
blast  could  not  equal  it.  Rocks  in  mountain  masses  are 
flung  into  the  air  like  pebbles,  and,  falling,  break  through 
the  yielding  crust,  and  disappear  in  the  boiling  abyss  be- 
neath. The  walls  of  the  chasm  are  now  uniting:  their 
pressure  forces  up  the  lava  in  fiery  fountains.  Fire 
and  water  are  struggling  for  the  mastery  with  the  wide 
world  for  an  arena.  Which  shall  conquer?  Turn  and 
view  that  muddy  ocean  behind  you  ;  its  turbid  waves 
dashing  against  the  rocky  shore  :  dense,  steamy  clouds 
hang  over  it  by  day  and  night,  whose  darkness  is  only 
relieved  by  the  numerous  fires  that  cast  a  lurid  glare  on 
the  vapory  envelope  of  the  globe. 


GRANITIC  AND  METAMORPIHC  PERIODS. 

AGE  OF  MINERALS. 

It  was  during  this  stormy  period  that  the  great  foun- 
dations of  the  globe  were  laid,  including  the  time  when 
the  granitic  and  metamorphic  rocks  were  deposited,  and 
before  life  had  made  its  appearance,  —  a  period  some- 
times called  the  azoic  age,  or  the  age  destitute  of  life : 
a,  in  Greek,  from  which  this  word  is  derived,  meaning 
"  without ;  "  and  zoe,  "  life." 

Were  I  asked  of  what  books  are  composed,  I  might 
say,  Of  chapters,  or  of  sentences  or  words  or  letters  (of 
which  there  are  twenty-six);  these  making  by  their 
combinations  the  hundred  and  twenty  thousand  words 
of  our  language.  So,  if  asked  of  what  the  earth 
is  composed,  I  might  say,  Of  various  formations,  or  of 
rocks  and  metals,  or  of  minerals  (of  which  we  have 


56  LECTURES  ON   GEOLOGY. 

about  seven  hundred),  or  of  elements  (about  sixty  of 
which  have  been  discovered).  These,  by  their  combina- 
tion, make  minerals,  as  letters  make  words ;  minerals 
make  rocks,  as  words  make  sentences ;  and  rocks  com- 
pose the  various  geologic  formations.  Of  these  sixty 
elements,  some  are  quite  rare,  and  many  are  only 
known  to  the  chemist ;  but  about  twelve  of  them  are  of 
practical  value,  and  the  student  of  geology  needs  to  be 
acquainted  with  them. 

Half  of  the  earth's  crust  is  oxygen, — an  invisible  gas. 
It  was  discovered  by  Priestley  in  1774.  It  is  the  sup- 
porter of  life  and  combustion.  Water  contains  nearly 
ninety  per  cent  of  it;  the  atmosphere,  more  than  twenty 
per  cent.  Sand  is  more  than  half  oxygen ;  and  lime- 
stone and  clay,  about  half;  one-half  of  the  globe,  as  we 
are  acquainted  with  it,  made  of  a  gas  that  no  man  ever 
saw,  tasted,  or  smelt ! 

One-quarter  of  the  earth's  crust  is  silicon, — the  base 
of  silica,  quartz,  sand,  and  flint;  which  are  silicon  com- 
bined with  oxygen:  when  thus  combined,  it  is  tho  prin- 
cipal ingredient  of  all  rocks  except  the  limestones.  In 
pure  water,  silica  cannot  be  dissolved ;  but  when  it  is 
very  hot,  or  when  it  is  warm,  and  contains  potash  or 
soda,  it  is  readily  dissolved,  and  may  then  be  deposited 
wherever  the  water  flows.  The  pores  of  organic  bodies 
buried  in  the  earth  have  in  this  way  frequently  been 
filled  with  silica,  and  the  shape  and  general  appearance 
of  them  preserved  for  ages. 

Another  important  element  is  aluminum,  —  a  white 
metal  between  tin  and  iron  in  many  of  its  qualities, 
but  light  as  chalk.  United  with  oxygen,  it  forms 
alumina,  which  is  pure  clay.  Common  clay,  of  which 
brick  is  made,  is  alumina  containing  impurities.  When 


LECTURES   ON  GEOLOGY.  57 

pure  alumina  is  crystallized,  it  forms  the  sapphire,  next 
in  hardness  to  the  diamond. 

Calcium  is  a  light-yellow  metal,  a  little  harder  than 
lead,  and  readily  unites  with  oxygen,  forming  quick- 
lime. Limestone  is  the  carbonate  of  lime,  formed  by 
the  union  of  carbonic  acid  and  lime.  When  put  into 
the  kiln,  the  carbonic  acid  is  driven  off  by  heat,  and 
quick-lime  is  left.  One  ton  of  good  limestone  yields 
about  eleven  hundred  weight  of  lime.  When  lime  and 
sulphuric  acid  unite,  the  result  is  sulphate  of  lime,  or 
gypsum,  found  in  immense  quantities  in  some  parts  of 
the  globe.  With  phosphoric  acid,  lime  forms  phosphate 
of  lime,  the  principal  ingredient  in  bones. 

Magnesium  enters  quite  largely  into  the  composition 
of  some  of  the  rocks.  It  is  a  white,  brilliant  metal, 
readily  uniting  with  oxygen;  when  it  forms  magnesia. 
This,  united  with  silica,  forms  hornblende,  talc,  soap- 
stone  (which  we  now  make  into  stoves),  and  serpentine. 

Iron  forms  nearly  two  per  cent  of  the  earth's  crust. 
It  is  very  seldom  found  in  its  native  condition,  except 
in  meteorites  j  but  is  found  combined  with  oxygen,  car. 
bon,  and  sulphur.  The  readiness  with  which  it  com- 
bines with  oxygen  may  be  seen  in  the  rust  so  easily 
formed  on  its  surface ;  rust  being  oxide  of  iron.  It  is 
very  abundant,  and  widely  diffused ;  being  found  in 
nearly  all  rocks  and  minerals. 

Potassium  is  a  silver-white  metal,  so  soft  that  it  may 
be  moulded  like  wax.  Its  affinity  for  oxygen  is  so 
strong,  that,  when  thrown  upon  the  surface  of  water,  it 
decomposes:  the  water  unites  with  the  oxygen,  form- 
ing potash,  and  liberates  the  hydrogen,  which  burns 
with  a  beautiful  flame.  Potassium  exists  chiefly  in 
felspar  and  clay,  and  constitutes  about  five  per  cent 
of  the  igneous  rocks. 


58  LECTURES    ON   GEOLOGY. 

Carbon  is  generally  found  united  with  oxygen  in  the 
form  of  carbonic  acid.  In  this  condition,  a  vast  amount 
is  locked  up  in  coal  and  lime.  The  atmosphere  con- 
tains about  one  part  in  twenty-five  hundred  by  weight 
of  this  gas ;  but,  before  the  coal  and  limestone  beds 
were  formed,  it  must  have  contained  vastly  more.  Char- 
coal is  nearly  pure  carbon;  and  the  diamond,  so  utterly 
unlike  it,  is  carbon  absolutely  pure  and  crystallized.  It 
is  estimated  that  nearly  two  per  cent  of  the  earth's 
crust  is  carbon. 

Hydrogen,  the  lightest  known  substance,  is  another 
somewhat  abundant  element.  It  forms  one-ninth  part 
of  water ;  and  since  water  enters  largely  into  the  com- 
position of  rocks,  gypsum  containing  twenty  per  cent 
and  serpentine  thirteen  per  cent,  hydrogen,  in  this  way, 
constitutes  about  half  per  cent  of  the  earth's  crust. 

Sodium,  a  light  metal,  and  chlorine,  a  heavy  gas,  con- 
stitute salt;  and  are  therefore  widely  distributed  upon 
the  surface  of  the  globe,  and  beneath  it.  Sodium,  in  the 
form  of  its  oxide  (soda),  is  contained  in  the  igneous  rocks 
generally.  Granite  contains  about  seven  per  cent. 

Lastly,  sulphur,  which  is  sometimes  found  in  a  per- 
fectly free  state,  but  more  frequently  in  combination 
with  the  metals,  as  iron,  lead,  copper,  &c. 

Of  these  elements,  nearly  the  whole  earth,  as  far  as 
we  are  acquainted  with  it,  is  composed.  By  union,  they 
form  the  various  minerals :  thus  silicon  and  oxygen 
make  quartz,  which,  ground  to  powder,  gives  us  sand ; 
and  this,  united  again  by  pressure,  makes  sandstone. 
Flint  is  a  variety  of  quartz.  In  its  various  forms, 
quartz  constitutes  one-half  of  the  earth's  crust. 

Silica,  uniting  with  alumina  (the  oxide  of  aluminum) 
and  potash  (oxide  of  potassium)  and  soda  (oxide  of  sodi- 


LECTURES   ON  GEOLOGY.  59 

um),  forms  felspar,  which  constitutes  one-tenth  of  the 
crust  of  the  earth.  Mica  is  composed  of  nearly  the  same 
materials  in  different  proportion. 

Limestone,  or  the  carbonate  of  lime,  which  is  formed 
by  the  union  of  carbonic  acid  (  carbon  and  oxygen)  with 
lime  (calcium  and  oxygen),  forms  about  one-seventh  of 
the  earth's  crust. 

Hornblende,  a  black  or  greenish-black  mineral,  which 
enters  into  the  composition  of  most  of  the  igneous  rocks, 
is  composed  of  silica  and  magnesia  (magnesium  and 
oxygen).  Hornblendic  rocks  are  very  tough,  and  dark 
in  color.  Talc,  a  soft  mineral,  sometimes  called  soap- 
stone,  having  a  greasy  feel,  and  chlorite,  a  mineral  some- 
what like  it,  are  composed  also  of  silica  and  magnesia. 

Most  of  these  minerals  must  have  existed  on  and  in 
the  earth  at  an  early  period,  and  long  before  life  made 
its  appearance. 

Fig.  1*  is  a  representation  of  the  various  rocks  com- 
posing the  earth's  crust,  in  the  order  in  which  they 
were  deposited.  The  lowest  is  granite,  generally  sup- 
posed by  geologists  to  have  been  produced  by  the 
cooling  of  the  original  fluid  mass  of  the  earth,  and 
hence  the  great  underlying  rock  of  the  globe, — 
that  on  which  all  the  others  have  since  been  de- 
posited, supporting  all  the  varied  geological  forma- 
tions, as  the  rock  or  soil  supports  the  houses  that  rise 
above  it.  Dig  where  we  please,  there  is  good  reason  to 
believe,  if  we  could  only  go  deep  enough,  that  we  should 
eventually  come  to  the  granite.  Strange  to  say,  though 
•the  granite  is  the  lowest  rock  of  all,  it  is  frequently 
found  on  the  tops  of  the  highest  mountains.  Thus 
granite  is  found  on  the  summit  of  Mount  Washington, 
the  highest  mountain  in  New  England;  on  Mont  Blanc, 
*  See  Frontispiece. 


60  LECTURES   ON  GEOLOGY. 

the  loftiest  mountain  in  Europe  ;  and  many  peaks  of  the 
Rocky  Mountains.  The  granite  found  on  the  tops  of  these 
mountains  doubtless  lay  at  a  great  depth  beneath  the 
surface  at  one  time,  but  has  been  heaved  up,  through 
the  rocks  that  lay  above  it,  to  the  position  that  it  now 
occupies ;  while  the  overlying  rocks  were  broken  through 
and  laid  upon  the  sides  of  the  mountains  thus  formed: 
and  hence  we  frequently  observe  rocks  on  the  surface 
that  were  once  miles  beneath  it,  and  obtain  a  knowledge 
of  the  earth's  interior  which  is  most  valuable. 

Granite  is  a  rock  well  known  in  New  England  (where 
it  is  quarried  in  numerous  places),  and  generally  in  the 
north  and  north-east  of  the  United  States,  by  numerous 
bowlders,  which  lie  scattered  over  the  country.  The 
color  varies  much  in  different  specimens, — in  some,  gray; 
in  others,  white  or  flesh-colored.  It  has  consolidated 
gradually  under  immense  pressure,  and  is  invariably 
crystalline  in  its  structure :  the  crystals  sometimes  are 
found  several  inches  in  diameter,  but  more  frequently 
not  more  than  an  eighth  or  a  quarter  of  an  inch.  True 
granite  is  composed  of  felspar,  quartz,  and  mica.  Quartz 
is  the  hardest  portion  of  the  granite,  and  will  readily 
scratch  glass.  It  has  a  bright,  glassy  appearance,  and 
breaks  into  angular  pieces  under  the  hammer. 

Felspar  is  not  quite  as  hard  as  quartz,  nor  yet  as 
bright,  and  is  more  readily  decomposed.  It  is  generally 
found  of  a  yellowish-white  color,  and  is  the  commonest  of 
all  substances  except  quartz  and  iron.  .  When  decom- 
posed, it  forms  a  white  clay,  which  is  used  in  the  manu- 
facture of  porcelain  and  china-ware.  It  is  known  in 
China  by  the  name  of  kaolin.  Upwards  of  twelve 
thousand  tons  are  carried  every  year  from  Cornwall  to 
-the  English  potteries. 


LECTURES   ON  GEOLOGY.  61 

Mica,  the  third  ingredient  of  granite,  improperly 
called  isinglass,  is  bright  and  shining  like  silver;  and 
is  so  soft,  that  it  may  be  scratched  with  the  finger-nail. 
It  can  be  readily  separated  into  thin  plates ;  and  in 
Siberia,  where  it  is  obtained  of  a  large  size,  it  is  used 
for  windows,  instead  of  glass.  Sheets  more  than  two 
feet  in  diameter  have  been  found  in  the  granite  of 
Acworth,  N.H.  It  is  frequently  used  in  the  doors  of 
stoves ;  for  the  heat  does  not  crack  it,  and  we  can  see 
the  cheerful  firelight  through  it.  It  has  been  used  for 
windows  on  board  of  men-of-war,  as  it  will  not  break  by 
the  concussion  of  the  guns. 

Felspar  generally  forms  the  principal  part  of  the  gran- 
ite. Sometimes  mica  is  absent,  and  hornblende  takes  its 
place  :  the  rock  is  then  termed  Sienite,  from  Syene  in 
Egypt,  where  it  was  supposed  to  abound.  When  mica 
is  also  present,  it  is  termed  Sienitic  granite.  When 
felspar  is  the  principal  ingredient,  the  quartz  and  mica 
being  very  rare,  it  is  called  felspathic  granite.  Many 
minerals  are  found  in  granite  ;  but  it  will  not  be  neces- 
sary for  me  to  refer  to  them. 

As  the  water  descended,  it  wore  down  this  granitic 
crust  ridged  up  by  the  cooling  of  the  earth,  just  as 
rivers  wear  down  rocks  to-day, —  more  rapidly  then,  how- 
ever ;  for  the  water  was  not  an  honest  combination  of 
oxygen  and  hydrogen  as  it  is  now,  but  more  like 
sulphuric  acid,  and  its  dissolving  power  was  much 
greater  than  water.  The  sediment  carried  down  was 
deposited  in  the  hollows  of  the  ocean,  and  here  a  new 
class  of  rocks  was  formed. 

As  two  grand  agents  have  been  concernccton  bringing 
the  world  to  its  present  position,  —  fire  and  water, —  we 
have,  as  the  result  of  their  operation,  two  classes  of  rocks, 


62  LECTURES   ON  GEOLOGY. 

— the  fire-made  and  the  water-made ;  but,  beside  these,  we 
have  a  third  class,  formed  by  water,  and  modified  by  fire. 
These  are  called  metamorphic  rocks,  so  called  from  the 
Greek  word  metamorp7io-o,  which  means  to  transform  ; 
these  rocks  being  changed  from  their  original  form.  At 
first,  laid  by  water  at  the  bottom  of  the  ocean  as  sedi- 
ment, they  have  a  stratified  appearance,  such  as  belongs 
to  the  water-made  rocks  :  but,  the  heat  passing  into  them 
from  the  underlying  fire-made  rocks,  in  many  cases 
they  have  become  melted,  and  in  others  very  much 
heated ;  so  that,  on  cooling,  they  have  crystallized,  and 
hence  have  the  appearance  that  belongs  to  the  crystal- 
line or  fire-made  rocks. 

Where  the  granite  was  worn  down,  and  carried  into 
and  laid  at  the  bottom  of  an  ocean  whose  waters  were 
disturbed,  so  as  to  mix  the  material  up,  the  sediment, 
forming  in  time  into  rock,  would  contain  all  the  ingredi- 
ents of  granite,  but  in  a  finer  form,  and  deposited  in 
layers.  Such  a  rock  is  gneiss  j  very  abundant  in  New 
England,  among  the  Rocky  Mountains  and  most  moun- 
tainous regions. 

The  quartz  of  the  granite  ground  to  powder  would  be 
sand  ;  this,  separated  from  the  other  ingredients  of  the 
granite,  and  deposited  in  an  ocean  whose  waters  were 
undisturbed,  would  by  pressure  make  sandstone  5  and 
this  sandstone,  heated  and  cooled,  forms  another  meta- 
morphic rock,  called  quartzite. 

The  felspar,  operated  upon  in  like  manner,  would  be 
formed,  first  into  beds  of  shale,  and  then  metamorphosed 
into  slate.  The  slate  with  which  we  cover  our  houses, 
and  on  which  our  children  write  at  school,  was,  it  is 
believed,  produced  in  this  way  from  the  felspar  of  the 
granite.  The  mica,  in  a  similar  manner,  formed  the  mica- 


LECTURES   ON  GEOLOGY.  63 

schists  or  mica-slates  which  make   such  beautiful  flag- 
ging for  our  streets. 

During  the  time  that  the  rocks  of  these  two  forma- 
tions were  deposited, — the  granitic  and  metamorphic, — 
it  appears  that  no  life  existed  on  the  globe  ;  no  bird  stirred 
the  heavy  air  with  its  wing ;  no  beast  trod  the  heated 
ground ;  no  fish  occupied  the  steamy  waters :  but  the 
grand  old  world  was  marching  steadily  on,  and  the 
ground  was  being  prepared,  from  which  fruitful  harvests 
in  future  ages  were  to  be  gathered. 

There  was  a  time  when  the  granitic  and  metamorphic 
rocks  covered  the  whole  globe :  on  them  the  waters 
rested,  and  of  them  the  land-surface  was  everywhere 
composed.  At  the  present  time,  however,  but  little  of 
this  primitive  surface  remains.  It  has  been  covered 
by  sediment,  carried  down  or  worn  down  by  the  waters ; 
and  only  those  portions  exist  which  have  not  been  worn 
away  or  under  water,  and  so  have  never  been  covered 
by  sediment.  Or  where  we  find  these  rocks  on  the 
surface,  in  mountain-regions,  they  have  been  elevated 
from  beneath  the  overlying  rocks ;  while,  in  still  other 
places  where  they  are  found,  the  rocks  that  once  lay 
above  them  have  been  swept  off  by  denuding  agencies 
operating  for  unnumbered  ages. 

In  Scotland,  they  cover  a  considerable  portion  of  the 
Highlands  and  islands.  The  north  of  Ireland,  and  the 
Wicklow  Mountains  in  the  east,  the  Cumberland  and 
Cornwall  Hills  in  England,  the  Alps  in  Switzerland,  and 
the  Pyrenees  in  Spain,  are  composed  of  them.  Large 
portions  of  the  mountain-regions  of  Asia,  Africa,  and 
America,  are  composed  of  rocks  belonging  to  this  age 
of  minerals. 

The  most  elevated  portions  of  the  Rocky  Mountains 


64  LECTURES  ON   GEOLOGY. 

are  composed  of  metamorphic  and  granitic  rocks.  The 
backbone  of  the  future  continent  —  the  present  line  of 
that  mountain-range  —  was  probably  indicated  at  a  very 
early  period. 

In  Canada,  we  find  a  belt  of  this  rock,  extending  from 
the  St.  Lawrence,  near  the  outlet  of  Lake  Ontario,  in  a 
north-eastern  direction  to  Labrador,  and  in  a  north- 
western direction  to  the  Arctic  Ocean ;  and  this  seems  to 
have  formed  the  nucleus  of  the  eastern  part  of  the  North- 
American  continent.  Slowly  elevated,  as  the  waters  of 
the  ocean  were  slowly  drained  off  by  the  deepening  of 
its  hollows,  there  were  deposited  around  this,  as  a 
centre,  the  younger  formations,  in  the  order  of  their  age ; 
so  that  we  can  behold  the  layers  of  the  continent's 
growth,  as  in  a  tree  we  see  the  rings  which  mark  its 
yearly  development. 


LECTURE    II. 


IP  a  man  should  commence  to  study  astronomy  with 
the  idea  firmly  fixed  in  his  mind  that  the  universe  is 
but  a  few  thousand  miles  in  diameter,  how  futile  would 
be  his  endeavors  to  master  the  grand  truths  of  this 
magnificent  science  !  With  such  a  contracted  notion  as 
this,  he  could  form  no  adequate  idea  even  of  the  stand- 
point from  which  he  observed  the  infinite  heavens.  So 
in  geology :  let  a  man  commence  to  study  it  with  a  firm 
persuasion  that  the  earth  is  but  a  few  thousand  years 
old,  and  what  can  he  ever  learn  of  geology  ?  He  has 
not  room  even  for  the  titlepage  of  the  mighty  volume 
spread  before  him :  he  cannot  even  account,  in  such  a 
scanty  period,  for  the  soil  that  lies  under  his  foot.  An 
enlarged  conception  of  the  element  of  time  is  absolutely 
essential  to  a  solution  of  the  geologic  problem. 

We  call  this  a  grand  old  world,  with  but  little  idea, 
sometimes,  of  the  great  significance,  in  this  connection, 
of  the  words  we  employ.  We  call  men  old  when  age 
has  whitened  their  locks,  unstrung  their  sinews,  and 
graven  their  faces  with  those  unmistakable  lines  which 
no  art  can  erase.  We  call  the  oak-tree  old  whose  giant 
trunk,  time-scarred  and  lichen-browned,  stands  in  majesty 
upholding  the  stalwart  branches  from  which  its  myriad 

5  65 


66  LECTURES   ON   GEOLOGY. 

twigs  their  leafy  banners  wave.  We  speak  of  old 
English  castles,  whose  ivy-crowned  ruins  have  inspired 
generations  of  poets,  whose  towers  looked  down  on  the 
feudal  barons  as  they  marshalled  their  vassals  for  the 
deadly  fray,  and  whose  halls  rang  with  the  wassail  revels 
of  the  olden  time.  The  Pyramids  of  Egypt  we  say  are 
old,  —  those  mighty  monuments  of  a  past  civilization,  that 
stood  on  their  firm  bases  when  Britain  was  an  island 
inhabited  only  by  savages  whose  dress  was  the  paint 
that  besmeared  their  bodies,  or  the  skin  torn  from  some 
wild  beast.  Yet  what  is  the  age  of  these  compared 
with  the  age  of  the  world  ?  They  are  the  veriest  babes 
of  time,  the  ephemera  of  a  summer's  day :  they  resemble 
the  bubbles  that  float  on  Niagara's  stream,  glittering  for 
an  instant  on  its  turbulent  breast,  then  disappearing  for- 
ever. 

Let  us  look  first  at  the  soil,  the  earth's  covering,  and 
the  youngest  thing  with  which  geology  deals.  A  tree 
was  cut  down  in  Calaveras  County,  California,  that 
measured  thirty-two  feet  in  diameter.  There  were  thir- 
teen rings  of  annual  growth  to  an  inch  of  it ;  so  that  the 
tree  was  2,496  years  old,  —  a  tree  that  was  a  sapling 
when  Nebuchadnezzar  was  a  boy,  that  was  nearly  two 
hundred  years  old  when  Socrates  was  born.  And  yet 
this  tree  is  by  no  means  the  oldest  vegetable  monument 
on  the  globe.  A  yew  at  Fortingall,  in  Scotland,  is  calcu- 
lated to  be  2,600  years  old;  and  one  at  Braburn,  in 
Kent,  3,000.  There  is  a  baobab-tree  at  Senegal,  in 
Africa,  in  which  an  incision  was  made,  and  the  concen- 
tric rings  counted  ;  and  from  that  it  was  calculated  to  be 
5,150  years  old.  Yet  there  is  a  cypress  in  Chapultepec, 
117  feet  in  circumference,  which  Humboldt  considers 
still  older. 


LECTURES  ON  GEOLOGY.  67 

The  soil  must  have  been  there  before  these  trees 
began  to  grow,  or  how  could  they  have  taken  root? 
The  parents  of  these  trees  must  have  had  soil  likewise 
for  their  growth.  Who  shall  say  how  many  generations 
of  such  trees  are  represented  by  this  soil?  what  ages 
were  spent  originally  in  pulverizing  the  hard  rock  to 
make  it  ?  What  historian  shall  write  the  biography  of 
these  twelve  inches  of  earth?  It  is  older  than  Britain 
and  the  Druids,  older  than  Gaul  end  the  Celts.  Greece 
the  ancient,  and  her  gods,  are  young  compared  with  it. 
Older  even  than  India,  the  grandfather  of  nations,  away 
into  the  shadowy  past  stretches  the  soil  we  so  carelessly 
tread  under  our  feet;  yet  the  age  of  the  soil  is  but  one 
of  the  days  of  the  earth's  vast  generation. 

Beneath  the  soil,  in  all  northern  countries^ne  beds  of 
sand,  gravel,  or  clay ;  and  mixed  with  these,  or  lying 
above  them,  are  rocks  known  by  the  name  of  bowlders, 
many  of  which  have  travelled  hundreds  of  miles  from 
the  places  they  originally  occupied.  Underlying  the 
soil,  they  were,  of  course,  laid  down  before  it.  Some  of 
the  beds  of  gravel  and  clay  belonging  to  the  drift,  as 
the  formation  is  termed  in  which  they  are  found,  are,  in 
places,  hundreds  of  feet  in  thickness,  indicating  the 
immense  period  of  time  occupied  in  their  formation.  In 
some  of  these  beds,  in  Great  Britain  and  Europe,  have 
been  found  the  bones  of  enormous  oxen,  nearly  as  large 
as  elephants;  bears  larger  than  the  great  grisly  of 
California;  monstrous  hyenas  and  elephants,  belonging 
to  species  now  no  more.  Daring  a  portion  of  the  time 
that  ihese  beds  were  being  deposited,  glaciers  thousands 
of  feet  in  thickness,  and  hundreds  of  miles  in  extent, 
moved  over  the  face  of  North  America,  Northern  Europe, 
and  Northern  Asia,  g'  hiding  down  the  rockn,  and  trans* 


68  LECTURES  ON  GEOLOGY. 

porting  vast  quantities  of  material  to  distant  localities. 
During  this  time,  also,  the  sea  occupied  much  of  what 
is  now  dry  land  ;  and  gigantic  icebergs,  laden  with  rocks 
and  debris,  went  sailing  toward  the  south,  and,  upon 
melting,  deposited  their  burdens  on  what  was  then  the 
floor  of  the  ocean,  —  now  much  of  it  land  occupied  by 
man. 

Below  these  drift  or  glacial  beds  lies  the  tertiary 
formation,  consequently  older  still.  It  consists  of  beds 
of  clay,  sand,  gravel,  marl,  sandstones,  and  limestones  ; 
having  a  thickness,  in  some  places,  of  thousands  of  feet. 
Some  of  these  beds  were  formed  at  the  bottoms  of  lakes; 
others  in  estuaries,  where  salt  and  fresh  water  inter- 
mingled; and  some  at  the  bottom  of  the  ocean.  In  them 
have  been  found,  in  Great  Britain,  multitudes  of  strange 
fruits,  and  remains  of  plants;  indicating  the  existence 
of  a  tropical  climate  there  daring  the  period  of  their 
growth,  which'  is  further  evident  from  the  character  of 
the  shells  associated  with  them,  many  of  which  belong 
to  genera  whose  living  representatives  are  found  only 
in  tropical  seas.  In  the  tertiary  beds  of  Germany  are 
large  deposits  of  brown  coal,  containing  trees,  in  one 
of  which  seven  hundred  and  ninety-two  rings  of  annual 
growth  were  counted.  Gigantic  turtles  and  tortoises, 
as  well  as  crocodiles,  have  been  discovered  in  some 
localities,  and  the  remains  of  many  extinct  beasts  :  the 
gypsum  quarries  of  Paris,  in  rock  belonging  to  this 
formation,  abound  with  their  bones. 

We  have  now  travelled  back  so  far  that  we  are  in  a 
new  world,  stranger  to  us  than  America  was  to  Colum- 
bus. The  Alps,  Himalaya,  and  Andes  lift  their  heads 
but  a  few  thousand  feet  above  the  surging  waves ; 
while  .^Etna  lies  slumbering  beneath  the  bed  of  the 


LECTURES  ON  GEOLOGY.  69 

Mediterranean,  then  covering  a  large  portion  of  North- 
ern Africa,  and  occupying  twice  the  space  it  does  at 
the  present  time.  Since  the  mountain-chains  deter- 
mine the  position  and  size  of  the  rivers,  how  different 
is  the  whole  face  of  the  land  !  The  ocean  covers  the 
spot  now  occupied  by  the  largest  cities ;  and  immense 
sea-monsters  disport  themselves  over  millions  of  square 
miles  now  occupied  by  man.  One-third  of  England  was 
covered  by  the  sea,  half  of  Ireland,  and  three-fourths 
of  Russia,  a  large  part  of  North  and  South  Carolina,  the 
whole  of  Florida,  a  large  portion  of  Louisiana  and  Mis- 
sissippi, all  the  eastern  portion  of  Texas,  and  a  great 
part  of  Alabama  and  Georgia.  It  might  be  supposed 
that  we  had  by  this  time  arrived  nearly  at  the  end  of 
our  journey:  but  we  have,  however,  only  fairly  com- 
menced our  travels  into  the  mighty  past;  and  untrodden 
realms  lie  still  before  us. 

Beneath  some  of  the  tertiary  beds  lie  beds  of  chalk : 
hence  we  discover  that  the  chalk  or  cretaceous  forma- 
tion is  older  than  the  tertiary.  From  the  materials  of 
which  it  is  composed,  we  learn  that  it  was  deposited  at 
the  bottom  of  the  ocean ;  and  from  its  thickness,  being 
with  its  accompanying  beds  of  clay  and  greensand 
nearly  two  thousand  feet  thick,  some  idea  may  be 
formed  of  the  vast  period  during  which  it  was  in  process 
of  deposition. 

Of  all  the  existing  animals,  not  one  has  been  able  to 
accompany  us  in  this  tremendous  journey :  all  we  find 
are  new  ;  the  familiar  islands,  rivers,  and  continents  are 
gone,  or  so  strangely  altered  that  we  no  longer  recog- 
nize them;  and  we  are  indeed  strangers  in  a  strange 
land. 

Cropping  out   from   beneath  the   chalk   in   England, 


70  LECTURES   ON  GEOLOGY. 

and  covering  a  considerable  portion  of  the  eastern  part 
of  the  island,  are  a  succession  of  beds  of  limestone, 
marl,  shale,  and  sandstone,  sometimes  termed  the 
oolitic  formation.  These  beds,  in  the  aggregate,  are 
more  than  two  thousand  feet  in  thickness  ;  and  since, 
in  places,  they  underlie  the  chalk,  were  evidently  depos- 
ited before  it. 

In  them  we  find  the  remains  of  gigantic  lizards,  that 
then  crawled  over  the  face  of  the  world  ;  one  genera- 
tion after  another  flourishing,  dying,  and  becoming 
entombed  in  muddy  deposits,  which  eventually  hard- 
ened into  rock. 

Below  them  are  found  beds  of  red  sandstone,  magne- 
sian  limestone,  salt,  gypsum,  and  marl;  some  of  the  beds 
of  salt  alone  being  hundreds  of  feet  in  thickness.  In 
some  of  the  sandstones  are  found  impressions  of  the 
feet  of  what  are  supposed  to  be  birds,  and  reptiles;  and 
some  that  seem  to  unite  the  characteristics  of  both, 
evidently  differing  considerably  from  all  existing  ani- 
mals. Farther  into  the  domain  of  ancient  Time  we 
are  marching ;  but  we  are  far  from  the  beginning  yet. 

Below  these  beds  are  the  coal-measures,  and  under- 
lying limestones  and  sandstones,  representing  by  their 
enormous  thickness,  in  some  places  from  ten  to  four- 
teen thousand  feet,  the  great  space  of  time  occupied  in 
their  deposition.  So  far  have  we  advanced,  that  all 
beasts,  and  even  birds,  have  perished  by  the  way :  one 
by  one  they  have  drooped  and  dropped  and  died;  and 
nothing  is  left  on  the  land  to  accompany  us  on  our 
journey  but  insects  and  a  few  frog-like  reptiles  that 
are  still  to  be  found  hopping  over  the  face  of  the  steam- 
ing ground. 

Below  these  come  the  Devonian  beds  of  sandstone, 


LECTURES   ON  GEOLOGY.  71 

limestone,  and  conglomerate ;  in  Scotland,  ten  thousand 
feet  in  thickness,  and,  in  some  parts  of  the  United 
States,  not  less ;  its  sandstones,  in  Scotland,  crowded 
with  mailed  fishes,  and  its  limestones  composed  of  the 
remains  of  shells,  corals,  and  other  marine  animals. 
What  vast  ages  must  be  represented  by  their  accumu- 
lated remains ! 

Beneath  the  Devonian  formation  we  find  the  Silurian, 
attaining,  in  England  and  Wales,  a  thickness  of  from 
twenty  to  thirty  thousand  feet,  composed  of  rocks  laid 
down  at  the  bottoms  of  ancient  oceans,  and  many  of 
them  as  full  of  the  remains  of  old  forms  of  life  "  as  a 
straw-stack  is  full  of  straws.77  What  time  spent  in 
building  these  mountain-monuments  of  the  dead  ! 

In  the  neighborhood  of  Perth,  Can.,  are  to  be 
seen  the  rocks  of  the  Laurentian  formation,  several 
thousand  feet  in  thickness,  in  which  a  few  obscure 
fossils  have  been  found.  With  trie  lowest  of  these  beds, 
all  life  has  vanished ;  and  we  march  into  the  night  of 
the  still  farther  past,  lighted  but  by  the  fitful  glare  of 
dread  volcanoes,  all  alone. 

Then  follow  the  metamorphic  rocks,  whose  thickness, 
on  the  flanks  of  the  Andes,  has  been  estimated  to  be 
from  ten  to  fifteen  miles ;  the  sediments  of  oceans  boil- 
ing hot,  worn  from  the  pre-existing  granite  by  the 
agency  of  water, —  that  granite  formed  during  ages 
numberless  from  the  cooling  of  the  original  igneous 
mass  of  the  globe.  What  an  immense  period  !  — "  an 
eternity,  all  but  the  name.77 

Having  obtained  some  faint  idea  of  the  vast  space  of 
time  during  which  our  planet  was  in  process  of  forma- 
tion, as  well  as  the  method  of  its  advance,  —  without 
which  we  should  grope  our  way  most  blindly  without 


72  LECTURES   ON   GEOLOGY. 

a  guiding  star,  —  we  can  now  walk  confidently  along 
its  pathway,  feeling  the  ground  at  every  step,  as  we 
consider,  in  ascending  order,  the  construction  of  the 
various  geological  formations,  and  see  how,  out  of  the 
original  chaos,  came  the  order  and  beauty  that  we  behold 
to-day. 

The  metamorphic  period  was  that  on  which  my  last 
lecture  closed,  —  a  period  indicated  by  those  immense 
beds  of  gneiss,  mica-schist,  talcose-schist,  slate,  and  con- 
glomerate, which  manifest  the  long  ages  of  desolation 
during  which  the  lifeless  globe  swung  round  the  sun, 
apparently  in  vain.  Our  planet  was  then  a  world  of 
belching  volcanoes  and  spouting  geysers,  of  heaving 
earthquakes  and  howling  tornadoes,  —  a  land  on  which 
the  sun  had  never  shone,  unblessed  by  the  smile  of 
the  moon,  unvisited  by  the  light  of  a  star.  Sulphurous 
clouds  canopied  it,  from  which  fell  dark  showers;  while 
black  torrents  poured  over  craggy  rocks  into  turbid 
oceans  that  lay  boiling  beneath  them. 

The  rocks  formed  during  this  period  are  destitute  of 
all  signs  of  life :  but  those  lying  immediately  above 
them  contain  what  are  called  fossils ;  and  these  are  of 
the  greatest  importance  to  the  geologist.  What  are 
fossils  ?  Animals  or  vegetables  buried  in  the  earth  by 
natural  causes,  and  preserved :  or  any  indications  of 
their  existence  found  in  the  rocks.  They  may  be  shells 
almost  unchanged,  as  these  post-pliocene  shells  from 
South  Carolina;  or  bones,  like  these  from  Colorado,  some- 
what heavier  than  they  were  originally,  by  the  infiltra- 
tion of  earthy  matter  into  their  pores ;  or  wood  changed 
into  flint-like  stone,  as  in  these  beautiful  specimens  from 
the  miocene  beds  of  Texas,  with  which  I  can  strike  fire 
just  as  readily  as  with  two  flints.  In  them  the  structure 


LECTURES   ON  GEOLOGY.  73 

of  the  wood  is  just  as  plainly  visible  as  in  wood  just 
detached  from  the  living  tree.  The  silica,  in  similar 
specimens,  has  been  removed  by  steeping  them  in 
hydro-fluoric  acid,  and  the  woody  fibre  found  so  well 
preserved,  that  it  could  be  used  in  determining  the 
genus  of  the  original  plant.  I  have  found  specimens 
partly  converted  into  stone ;  the  rest  lignite,  still  retain- 
ing much  of  its  original  woody  character.  Wood  has 
been  found  in  a  Roman  aqueduct  partially  converted 
into  stony  matter ;  and  the  stave  of  a  cask  which  had 
been  in  the  well  of  the  Castle  of  Gotha  for  a  hundred 
and  fifty  years  was  so  petrified  by  the  oxide  of  iron  as 
to  take  a  polish  by  friction. 

A  fossil  may  also  be  the  cast  of  an  animal  or  plant. 
Sometimes,  when  shells  are  buried  at  the  bottom  of  the 
ocean  or  lakes,  mud  is  pressed  in,  or  filters  in,  and  fills 
the  cavity  of  the  shell.  This  mud,  in  time,  hardens  into 
rock ;  while  the  shell  on  the  outside  decays,  and  is 
removed  by  infiltration.  The  cast  of  the  inside  of  the 
shell  thus  formed  is  a  fossil  as  truly  as  the  shell  itself; 
and  in  some  rocks  they  are  the  only  fossils  we  find.  In 
mud-banks  on  the  coast  of  Nova  Scotia,  I  have  seen  mul- 
titudes of  such  fossils  in  process  of  formation,  —  the 
mud  in  the  shell  half  hardened  into  rock,  and  the  shell 
partly  decayed.  Similar  specimens,  less  advanced,  I 
have  also  seen  dug  out  of  the  Erie  Canal,  New  York ; 
also  brought  up  by  a  dredging-machine  at  St.  Joseph, 
Mich. 

In  some  cases,  animals  have  walked  over  mud ;  and 
this,  hardening  into  rock,  has  preserved  the  track  made 
upon  it,  producing  a  fossil  footprint.  The  marks  of  rain- 
drops, ripple-marks,  and  sun-cracks,  have  been  preserved 
in  a  similar  manner ;  and,  though  not  organic,  they  are 


74  LECTURES   ON  GEOLOGY. 

of  the  greatest  service  in  reading  aright  the  past  hi* 
torj  of  the  globe. 

These  fossils  are  the  letters  in  which  the  history  of 
the  world  is  written ;  and  without  their  assistance  we 
should  not  have  known  the  past  history  of  our  planet 
probably  for  ages  to  come. 

By  them  we  decide  the  comparative  ages  of  rocks,  — 
a  matter  of  the  greatest  importance.  Certain  forms  of 
Kfe  lived  at  certain  times,  and  their  remains  became 
buried  in  the  sediments  deposited  during  those  times : 
hence,  when  we  find  rocks  containing  fossil-forms  with 
which  we  are  acquainted,  we  can  refer  those  rocks  at 
once  to  that  period  in  the  world's  history  when  we 
know  those  forms  of  life  existed.  Thus  in  the  rocks  at 
Cincinnati,  0.,  at  Ottawa,  Can.,  at  Trenton  Falls,  N.Y., 
and  at  Dudley,  Eng.,  we  find  similar  fossil-forms, 
and  refer  the  rocks  to  the  Silurian  formation ;  for  the 
animals  whose  remains  we  find  in  them  lived  at  that 
period,  and  no  other.  Rocks  that  are  separated  by  many 
thousands  of  miles  are  thus  known  to  be  identical  in 
age,  or  nearly  so ;  and,  the  farther  we  go  back  in  time, 
the  more  certain  we  may  be  of  this,  the  general  con- 
dition of  the  earth  and  ocean  being  similar  over  the 
entire  globe  at  an  early  period  in  its  history. 

When  we  find  in  certain  beds  the  remains  of  land- 
plants,  of  fresh-water  shells  and  fishes,  and  of  land-ani- 
mals, we  may  feel  sure  the  deposits  were  made  in  a  lake 
of  fresh  water;  but  if  we  find  strata  containing  land- 
plants  and  sea-plants,  marine  shells  and  bones  of  land 
animals,  mixed  confusedly  together,  we  may  know  that 
we  are  examining  a  deposit  made  by  a  river  pouring 
sediment  into  the  sea.  When  all  the  forms  are  marine, 
which  can  readily  be  known,  they,  in  like  manner, 


LECTURES   ON  GEOLOGY.  75 

speak  of  the  condition  of  their  formation ;  and  we  can 
even  tell  whether  the  sea  was  deep  or  shallow  by  the 
prevalence  of  certain  forms. 

Nearly  all  the  rocks  above  the  metamorphic  contain 
more  or  less  fossils ;  and  in  many  parts  of  the  country 
they  are  almost  exclusively  composed  of  them:  this  is 
especially  the  case  with  limestones.  About  twenty 
thousand  fossil-shells,  which  are  the  most  readily  pre- 
served of  all  bodies,  are  already  known  j  and  that  num- 
ber will  doubtless  be  more  than  quadrupled  when  the 
crust  of  the  earth  has  been  thoroughly  examined. 

By  fossils  we  learn  that  the  earth  has  been  inhabited 
by  living  beings  for  millions  of  years,  rising  higher  and 
higher  in  the  scale ;  that  death  has  swept  away  individu- 
als and  species,  but  only  that  life  might  supply  new 
individuals  and  more  advanced  species.  They  enable 
us  to  answer  a  thousand  questions  that  the  inquisitive 
soul  of  man  is  ever  asking;  and,  when  they  do  not 
fully  answer  them,  they  yet  give  much  light  and  satis- 
faction. Where  did  life  begin  ?  On  the  mountain-top, 
among  the  silent  clouds,  and,  descending,  spread  over 
the  newly-formed  valley ??  by  the  river-side,  in  the  slime 
left  by  its  overflowing  waters,  so  well  calculated  to 
nourish  the  vital  germs  ?  on  the  undulating  surface  of 
the  land,  warm  and  steaming  from  the  internal  fires  and 
descending  torrents  ?  Or  did  it  commence  in  the  world- 
embracing  oceans,  whose  heaving  waters  laved  the  dark 
islands  that  dotted  its  wide  surface  ?  And  what  were 
the  first  organized  existences  ?  Pines  wagging  their  heads 
on  the  hill-tops?  fruit-trees  bending  beneath  their  blush- 
ing load  ?  grass  carpeting  the  valleys  with  velvet, 
beautifying  the  earth  previous  to  its  occupancy  by  its 
grand  controller,  man?  Were  elephants  the  first  occu« 


76  LECTURES   ON  GEOLOGY. 

pants,  shaking  the  ground  with  their  tread  ?  or  timid 
rabbits  peeping  from  their  burrow  ?  whales  in  the 
ocean,  or  minnows  sporting  in  the  brook  ?  Had  it  been 
left  to  man's  imagination  to  decide,  we  should  probably 
have  had  monsters  as  tall  as  the  steeple-tops  striding 
over  the  face  of  the  young  earth.  But  how  much 
simpler  is  Nature  than  man's  imagination  1  Not  on 
the  mountain-top  did  life  commence ;  for  the  crust  of 
the  earth  was  thin,  and  unable  to  bear  the  weight  of  the 
mountains :  they  were  then  unborn.  Life  did  not  com- 
mence on  the  land  ;  for  the  land-surface  of  the  globe 
was  a  wilderness  of  bare  and  heated  rock  ;  and  life  upon 
it  was  an  impossibility.  The  first  fossils  we  find  give 
us  reason  to  believe  that  life  commenced  in  very  sim- 
ple forms,  and  in  the  ocean  ;  that  the  first  living  inhabit- 
ants drew  their  nourishment  from  her  ample  bosom. 

To  understand  what  the  first  animals  were  like  whose 
remains  are  found  in  the  rocks,  it  will  be  necessary  to 
call  in  the  aid  of  zoology,  or  the  science  which  treats  of 
animals.  Most  zoologists  place  all  the  animals  of  the 
world  in  four  grand  divisions,  or,  as  they  are  sometimes 
called,  sub-kingdoms. 

These  are  RADIATA,  MOLLUSCA,  ARTICULATA,  and  VERTE- 
BRATA.  First,  the  radiata,  or  ray-like  animals.  These 
are  generally  circular,  having  all  the  parts  of  the  body 
disposed  in  a  radiated  form,  which  often  gives  them 
the  shape  of  a  flower.  The  parts  generally  consist  of 
five.  The  star-fish  have  five  fingers ;  the  crinoids,  five 
sides,  five  arms,  and  their  fingers  are  ten,  twenty,  or 
some  other  multiple  of  five.  This  division  includes 
the  sponges,  corals,  star-fishes,  and  all  those  animals 
known  as  zoophytes,  or  plant-animals ;  because,  although 
animals,  they  much  resemble  plants  in  appearance; 


LECTURES   ON  GEOLOGY. 

being  destitute  —  as  is  the  case,  probably,  with  all  the 
radiata  —  of  head,  eyes,  or  at  least  what  we  call  eyes, 
and  organs  of  sensation  generally,  except  feeling ; 
though  some,  like  the  sponge,  do  not  even  manifest  this. 
They  seem  to  be  little  more  than  animated  stomachs, 
"  that  eat  and  drink ;  and  then  —  why,  simply  eat  and 
drink  again."  (It  is  a  pity  that  some  of  the  higher 
vertebrates  so  much  resemble  them.)  The  star-fish  and 
the  sea-urchin,  or  sea-egg,  may  be  taken  as  representa- 
tives of  the  radiata,  which  are  generally  found  in  the 
ocean,  and  in  great  numbers.  The  hydra,  or  fresh-water 
polyp,  one  of  the  few  not  confined  to  the  ocean,  may 
be  cut  into  a  number  of  pieces :  each  piece  will  grow 
into  a  perfect  animal ;  and  "  even  a  small  portion  of  the 
skin  soon  grows  into  a  polyp."  One  species  may  be 
turned  inside  out  like  a  glove,  the  skin  on  the  outside 
performing  the  office  of  a  stomach  inside ;  the  animal 
just  as  ready  to  take  his  breakfast  as  before.  The 
present  seas  contain  about  ten  thousand  species  of  radi- 
ates. The  simple  forms  of  life  belonging  to  the  radiata 
have  played  a  very  important  part  in  the  past  history  of 
the  globe. 

The  molhisca,  whose  name  is  derived  from  moUis,  the 
Latin  word  for  "  soft,"  includes  those  animals  which  pos- 
sess soft  bodies,  are  destitute  of  a  bony  skeleton,  and  gen- 
erally covered  with  a  hard,  protectkig  shell.  They  are 
higher  in  the  scale  than  the  radiata,  having  a  distinct 
neivous  centre  ;  while  many  of  them  possess  a  head, 
eyes,  organs  of  hearing,  and  perhaps  of  smell.  They 
have  a  heart,  with  arteries  and  veins,  through  which 
their  cold,  colorless  blood  circulates. 

The  mollusks  are  divided  into  six  classes,  four  of 
which  are  very  important  to  the  geologist. 


78  LECTURES   ON  GEOLOGY. 

First,  The  cephalopoda,  or  head-footed  mollusks ;  de- 
riving their  name  from  the  muscular  arms  or  tentacles 
that  surround  the  head,  as  in  the  cuttle-fish  and  the 
nautilus. 

Second,  The  gasteropoda,  or  belly-footed  mollusks,  as 
the  garden-snail  and  sea-snail,  creeping  on  a  broad,  mus- 
cular foot  (whence  their  name),  and  usually  provided 
with  spiral,  univalve  shells  ;  that  is,  shells  of  one  valve 
or  piece. 

Third,  The  brachiopoda,  or  arm-footed  mollusks ;  so 
called  because  their  organs  of  motion  resemble  the 
"  arms  "  of  some  polyps.  Their  shells  so  much  resemble 
antique  lamps,  that  they  used  to  be  termed  lamp-shells. 
The  hole  which  admits  the  wick  in  a  lamp  serves  in  the 
brachiopod  for  the  passage  of  a  footstalk,  by  which  it 
attaches  itself  to  objects  at  the  bottom  of  the  sea. 

But  few  of  the  brachiopodous  shells  are  to  be  found 
in  our  present  seas :  they  were,  however,  very  abundant 
in  the  ancient  oceans. 

Fourth,  The  conchifera,  or  shell-bearers,  as  the  term 
implies,  includes  the  oysters,  scallops,  muscles,  and 
clams,  so  well  known  by  everybody. 

The  third  grand  division  of  the  animal  kingdom,  is  the 
articulata.  The  name  is  derived  from  articulus,  —  Latin 
for  "  a  little  joint."  It  includes  the  ringed  or  jointed  ani- 
mals, —  worms,  crabs  and  lobsters,  beetles  and  flies. 

In  the  articulata,  the  brain  is  in  the  form  of  a  ring 
encircling  the  gullet.  The  body  is  symmetrical,  —  one 
side  like  the  other;  and  the  skeleton  is  external,  and 
consists  generally  of  horny  rings. 

The  articulates  are  the  most  numerous  of  all  animals 
at  the  present  day,  and  probably  were  during  many  of 
the  geologic  periods ;  but  they  are  so  slight,  and  so  easily 


LECTURES   ON  GEOLOGY.  79 

destroyed,  that  it  is  difficult  to  find  perfect  specimens  in 
any  of  the  rocks. 

The  last  grand  division  is  the  vertebrata,  or  backboned 
animals  j  vertebra  being  the  Latin  word  for  "  backbone." 
This  division  includes  all  animals  possessing  an  internal, 
jointed  skeleton.  They  possess  a  brain,  protected  by  a 
bony  case ;  and  are  superior  to  all  other  animals  in  the 
perfection  of  their  organs  of  sensation.  The  vertebrata 
are  divided  into  four  classes, — fishes,  reptiles,  birds, 
and  mammals,  or  animals  that  give  suck  to  their  young, 
—  commonly  called  beasts. 

A  zoologist  giving  a  list  of  the  various  kinds  of  ani- 
mals from  the  highest  to  the  lowest  would  give  them  in 
the  following  order  :  — 

MAN. 

MAMMALS  BELOW  MAN. 

BIRDS. 

REPTILES. 

FISHES. 

ARTICULATES. 

MOLLUSKS. 

RADIATES. 

There  might  be  some  difference  of  opinion  about  the 
position  of  the  mollusks,  whether  they  should  be  placed 
above  or  below  the  articulates  ;  and  it  might  be  ques- 
tioned whether  there  are  not  animals  lower  in  the  scale 
than  the  radiates.  With  these  exceptions,  all  zoologists 
(those  worthy  of  the  name)  who  lived  before  geology  was 
known  as  a  science,  as  well  as  those  who  live  now, 
would  represent  the  animals  of  the  world  as  they  are 
represented  above.  It  is  certainly  a  remarkable  fact, 


80  LECTURES   ON  GEOLOGY. 

that  a  list  almost  if  not  entirely  identical  with  this  had 
been  made  out  in  the  rocks  long  before  man  began  to 
think  upon  this  subject.  The  order  as  we  find  it  in  the 
rocks  is,  — 

RADIATES. 

ARTICULATES. 

MOLLUSKS. 

FISHES. 

REPTILES. 

BIRDS. 

MAMMALS  BELOW  MAN. 

MAN. 

There  is  a  similar  difficulty  in  this  list  in  deciding 
whether  mollusks  or  articulates  are  found  earliest  in  the 
rocks  ;  otherwise  this  is  the  order  which  geology  has 
developed  as  existing,  indicating  the  successive  forms 
of  life  that  have  appeared  upon  the  globe.* 

*  As  there  has  been  some  dispute  on  this  subject,  especially  with  regard 
to  the  geological  position  of  vertebrates,  and  statements  conflicting  with 
those  just  presented  have  been  made  by  some  who  are  regarded  as 
authorities  on  this  continent,  it  may  be  well  to  quote  some  of  the  recog- 
nized authorities  on  this  subject.  Sir  Charles  Lycll,  in  his  Antiquity  of 
Man,  1863,  p.  403,  says,  "No  remains  of  any  vertebrate  animal  have  yet 
been  discovered  in  the  lower  Silurian  strata,  rich  as  these  are  in  inverte- 
brate fossils  ;  nor  in  the  still  older  primordial  zone  of  Barrande."  Professor 
Owen,  the  greatest  living  naturalist  and  comparative  anatomist,  says  in  his 
Paleontology,  1861,  p.  119,  "  The  earliest  good  evidence  which  has  been 
obtained  of  a  vertebrate  animal  in  the  earth's  crust  is  a  spine,  of  the  nature 
of  the  dorsal  spine  of  the  dog-fish,  and  a  buckler  like  that  of  a  placo-ganoid 
fish.  Both  have  been  found  in  the  most  recent  deposits  of  the  Silurian 
period,  in  the  formation  called  upper  "  Ludlow  rock."  Since  then,  it  has 
been  stated  that  fish  remains  are  found  in  the  lower  Ludlow  in  Hereford- 
shire ;  but,  lower  than  this,  there  is  no  good  evidence  of  the  existence  of  fish. 
In  America,  we  have  no  certain  evidence  of  fish  remains  in  any  Silurian 
bed.  Between  the  Llanberris  slates  at  Bray  Head,  in  Ireland,  in  which  the 


LECTURES   ON  GEOLOGY.  81 

When  the  question  is  asked,  "  What  were  the  first 
life-forms  ?  "  we  may  not  be  able  to  hold  up  a  fossil,  as  I 
have  heard  of  a  lecturer  doing,  and  say,  "  This,  gentle- 
men, is  the  first  animal  that  God  Almighty  ever  made  ; " 
for  we  can  never  know  that  the  earliest  form  we  find  is 
the  earliest  that  ever  existed.  We  can,  however,  see  in 
the  constantly-increasing  simplicity  of  living  beings,  as 
well  as  their  decreasing  size,  as  we  go  backward  in 
time,  a  clear  indication  of  what  it  must  have  been  like. 


CAMBRIAN  AND  LAURENTIAN  PERIODS. 

AGE    OF  RADIATES. 

The  earliest  fossil  forms,  or  those  found  in  the  lowest 
or  oldest  rocks  up  to  this  time,  are  radiates.  The  oldest 
rocks  in  England,  Wales,  and  Ireland,  which  contain 
fossils,  hav,e  been  called  the  Cambrian  formation,  from 
Cambria,  the  ancient  name  of  Wales.  It  consists  princi- 

oldest  known  fossils  are  found,  and  the  "  lower  Ludlow,"  in  which  are  the 
earliest  fish  remains,  are  beds  crowded  with  the  remains  of  radiates, 
mollusks,  and  articulates,  no  less  than  twenty-four  thousand  feet  in  thick- 
ness, and  representing,  therefore,  millions  of  years.  So  far  are  all  the  great 
types  from  appearing  "  simultaneously,"  as  has  been  affirmed.  If  fish 
should  ever  be  discovered  in  the  lower  Silurian,  as  they  probably  will, 
still  there  will  be  in  Europe  the  immense  thickness  of  the  Cambrian  beds, 
with  their  invertebrate  fossils  below  them;  and  in  America  the  twenty 
thousand  feet  of  the  Laurentian  group,  in  which  radiate  fossils  alone  are 
found. 

Even  Agassiz,  who  has  so  frequently  affirmed  that  "  vertebrates  have 
always  existed  side  by  side  with  radiates,  mollusks,  and  articulates,"  and 
whose  example  has  led  others  to  make  a  similar  statement,  says  in  his 
Essay  on  Classification,  p.  43,  that,  since  the  four  great  branches  of  the 
animal  kingdom  are  everywhere  found  together  now,  he  considers  it  a 
"  sufficient  reason  to  believe  that  fishes  will  be  found  in  those  few  fossil- 
iferous  beds  in  which  thus  far  they  have  not  been  found." 
6 


82  LECTURES   ON  GEOLOGY. 

pally  ol  beds  of  sandstone  and  slate,  and  is  divided  into 
the  lower  and  the  upper  Cambrian.  In  the  lower 
Cambrian  are,  first,  the  Llanberris  slates,  which  have  a 
thickness  variously  estimated  at  from  one  to  six  thousand 
feet ;  above  these,  the  Harlech  Grits,  five  hundred  feet. 
The  lower  Cambrian  of  Cumberland,  England,  is  esti- 
mated by  Professor  Sedgwick  at  six  thousand  feet.  In 
the  lower  part  of  the  lower  Cambrian,  at  Bray  Head,  in 
Ireland,  four  species  of  a  zoophyte  have  been  discovered, 
to  which  the  name  of  Oldhamia  has  been  given,  after 
its  discoverer.  This  ancient  radiate  form  is  regarded  at 
the  present  time  as  the  oldest  European  fossil ;  and  its 
simplicity  corresponds  with  what  we  might  reasonably 
expect  from  the  earliest  life-forms, — solid  enough  to 
leave  an  impress  on  the  rock.  "  One  species,"  says  Owen, 
u  presents  an  axis  with  radiating  groups  of  branches 
diverging  alternately  at  regular  intervals  from  either 
side.  The  original  flexibility  of  the  compound  organism 
is  shown  by  the  confused  and  compressed  state  in  which 
the  whole  mass  is  sometimes  found,  and  from  the  more 
or  less  folded  state  of  the  little  fans."  Dr.  Kinahan  says, 
"  They  have  regularity  of  form ;  abundant,  but  not  uni- 
versal occurrence  in  beds;  and  are  permanent  in  charac- 
ter, —  even  when  the  beds  are  at  a  distance  from  each 
other,  and  dissimilar  in  chemical  and  physical  character." 

The  upper  Cambrian  consists  of  the  Lingula  Flags, 
about  two  thousand  feet  thick  ;  deriving  its  name  from  the 
lingula,  a  small  bivalve  shell,  —  that  being  the  most  com- 
mon fossil  in  it ;  though  it  also  contains  radiate  forms, 
and  some  small  crustaceans.  Above  these  are  beds, 
principally  of  slate,  estimated  at  eight  thousand  feet, 
containing  but  few  fossils,  —  zoophytes  and  crustaceans. 

There  is  a  formation  in  America,  generally  believed  to 


LECTUEES   ON   GEOLOGY.  83 

be  older  than  the  Cambrian :  it  is  known  by  the  name  of 
the  Lauren tian  formation  (from  the  River  St.  Lawrence). 
It  consists  of  beds  of  gneiss,  quartzite  and  crystalline 
limestones  ;  and  is  said  to  be  twenty  thousand  feet  in 
thickness.  It  is  found  along  the  north  side  of  the  St. 
Lawrence,  and  stretches  to  Labrador  on  the  east,  and 
to  Lake  Huron  on  the  west.  These  rocks  have  been 
called  by  some  the  oldest  on  the  globe,  and  by  others 
the  oldest  on  this  continent ;  but,  till  the  earth  has  been 
more  fully  examined  ty  geologists,  such  statements 
cannot  be  relied  on.  There  is  no  doubt,  however,  of 
their  great  age, — far  greater  than  that  of  rocks,  generally 
supposed,  previous  to  recent  discoveries,  to  be  the  oldest 
fossiliferous  rocks  on  the  globe. 

These  rocks  had  been  long  suspected  to  contain 
fossils,  and  bodies  had  been  found  in  them  which  very 
much  resemble  fossil  corals ;  but  they  had  been  so 
much  altered  by  heat,  that  it  was  difficult  to  speak  posi- 
tively with  regard  to  them.  Professor  Dawson  of  Mon- 
treal has,  however,  found  in  these  rocks  what  he  re- 
gards as  shells  of  rliizopods.  The  name  is  derived  from 
the  Greek  rhiza,  " root ; "  pous,  "  foot : "  they  are  root-foot- 
ed animals,  whose  shells  are  full  of  holes,  through  which 
pass  a  number  of  filaments,  looking  like  roots,  by  which 
they  lay  hold  of  bodies,  and  so  pull  themselves  along. 
These  animals  are  extremely  simple  in  their  organiza- 
tion, being  destitute  of  a  mouth  and  stomach :  they  seem 
to  be  as  near  the  lowest  round  of  the  ladder  of  life  as  we 
can  imagine  an  animal  to  be.  If  these  should  prove  to 
be  fossils,  as  they  are  now  generally  regarded,  they  take 
us  nearest  to  that  wonderful  morn  when  life  first  ap« 
peared  upon  the  globe. 

In   this   age  of  radiates    I    include    rocks    in  which 


84  LECTURES   ON   GEOLOGY. 

mollusks  and  articulates  are  found ;  for  radiates  seem  at 
the  time  of  their  deposition  to  have  been  most  abundant 
and  most  diversified.  Thus  in  the  upper  Cambrian  are 
cystideang,  crinoids,  corals,  and  graptolites, —  all  radiate 
forms,  and  representing  the  three  classes  into  which 
they  are  divided.  It  is  probable  that  unnumbered  ages 
passed  away  previous  to  the  deposition  of  these  beds, 
during  which  radiates  were  the  only  existing  organisms ; 
but  the  forms  were  too  slight  to  leave  a  fossil  impress, 
or  they  have  subsequently  beefc  obliterated  by  the  heat 
to  which  they  have  been  subjected.  Life  marched  but 
slowly  in  the  early  fossiliferous  periods  ;  and  it  must  have 
been  long,  long,  after  its  first  appearance,  before  the 
vertebrate  type  was  possible. 


SILURIAN   PERIOD. 

AGE    OF  SHELLS,    OR   MOLLUSKS. 

Above  the  Laurentian  and  Cambrian  beds  we  find  a 
succession  of  limestones,  shales,  and  sandstones,  known 
by  the  name  of  the  Silurian  formation,  so  called  from  the 
Silures,  a  tribe  of  ancient  Britons  who  lived  in  the  west 
of  England,  where  the  rocks  of  this  formation  lie  on  the 
surface,  where  their  peculiar  fossils  are  abundant,  and 
where  this  formation  was  first  studied. 

Both  in  England  and  America,  the  Silurian  formation 
has  been  divided  into  lower  Silurian  and  upper  Silu- 
rian, certain  fossils  characterizing  these  divisions  in 
both  countries ;  that  is,  certain  fossil  forms  are  found  in 
them  that  are  found  nowhere  else,  and  which  enable  the 
geologist  to  identify  the  rocks  containing  them  at  sight. 
In  the  United  States,  and  especially  in  the  State  of  New 


LECTURES  ON   GEOLOGY.  85 

York,  where  the  various  beds  of  this  formation  are 
widely  exposed  and  their  fossils  very  numerous,  many 
distinct  groups  of  rocks  have  been  made  out,  each  having 
some  fossils  that  distinguish  it. 

The  following  groups  of  rocks  constitute  the  Silurian 
formation  as  it  is  developed  in  the  State  of  New  York, 
commencing  at  the  top :  — 

Upper  Silurian. 

LOWER  HELDERBERG  LIMESTONE. 
ONONDAGA  SALT  GROUP. 
NIAGARA  GROUP. 
.     CLINTON  GROUP. 
MEDINA  SANDSTONE. 
ONEIDA  CONGLOMERATE. 

Lower  Silurian, 
HUDSON-RIVER  GROUP. 
TRENTON  LIMESTONE. 
BLACK-RIVER  LIMESTONE. 
BIRD'S-EYE  LIMESTONE. 
CHAZY  LIMESTONE. 
CALCIFEROUS  SANDSTONE. 
POTSDAM  SANDSTONE. 

Below  these,  in  British  America,  are 

HURONIAN, 
LAURENTIAN, 

which  are  included  by  some  geologists  in  the  Silurian. 

The  lowest  of  these  groups,  the  Potsdam  sandstone, 
derives  its  name  from  Potsdam  in  St.  Lawrence  Courty, 
New  York;  where  it  is  about  sixty  feet  thick.  It 


86  LECTURES   ON  GEOLOGY. 

occurs  on  the  south  shore  of  Lake  Superk  r,  in  Texas, 
and  in  Wisconsin ;  where  it  is  said  to  attain  a  thickness 
of  seven  hundred  feet.  There  is  no  doubt  that  it  under- 
lies a  large  portion  of  the  continent,  having  been  covered 
up  by  more  recent  deposits.  The  number  of  fossils  found 
in  it  is  not  large :  this  may  be  partly  owing  to  the  sub- 
stance of  which  it  is  composed;  sand  being  an  unfavor- 
able material  for  the  preservation  of  organic  forms. 
F.  2  One  of  the  most  characteristic  is  a 

small  bivalve  called  Lingula  prima 
(lingula  meaning  "little  tongue;"  and 
prima,  "first");  the  first  part  of  the 
name  describing  the  shape  of  the  shell, 
and  the  other  its  supposed  position  in 
time. 

In  Wisconsin,  many  forms  of  trilo 
bites  have  been  discovered  in  it ;  some 
slabs  being  covered  with  the  casts  of 

Dikelocephalus  Minnesota.  ^^        yig>   g  represents  Qne  from  the 

Potsdam  sandstone,  Mazomania,  Wis. 

The  trilobite  was  an  articulate  animal  covered  with 
a  thin  crust,  or  shell ;  and  varied  in  size,  from  that  of  a 
small  beetle  to  a  large  crab  or  lobster.  The  head,  which 
was  crescent-shaped,  was  furnished  with  two  eyes, 
composed  of  a  number  of  lenses  like  those  of  a  dragon- 
fly, which,  in  many  species,  have  been  beautifully  pre- 
served. The  body  was  composed  of  many  small  plates, 
folded  over  each  other  as  they  are  in  the  tail  of  a 
lobster,  and  divided  lengthwise  by  two  furrows  into  three 
lobes,  from  which  the  name  of  trilobite  was  given  to  it. 
They  appear  to  have  swarmed  in  the  early  oceans  as  the 
shrimps,  prawns,  and  crabs  do  now,  or  as  the  king-crabs 
on  the  New-Jersey  coast,  —  animals  that  more  nearly 


LECTURES  ON  GEOLOGY.  #7 

resemble  the  trilobite  than  any  others  found  on  our 
Atlantic  shore.  Hundreds  of  species  have  been  dis- 
covered; and  hundreds  more,  doubtless,  remain  to  be 
discovered. 

Most  of  the  fossil  forms  found  in  the  Potsdam  sand- 
stone are  small ;  but,  in  the  geological  rooms  at  Montreal, 
tracks  of  what  appear  to  have  been  large  crustaceans 
of  some  kind  may  be  seen.  Some  of  these  tracks  are  in 
parallel  lines,  and  not  less  than  seven  inches  wide. 

It  is  not  uncommon  to  find  upon  slabs  of  this  sandstone 
wavy  appearances,  that  plainly  indicate  ripple-marks  made 
on  the  shore  of  a  shallow  sea.  Several  species  of  fu- 
coids,  or  seaweeds,  have  been  discovered  in  it  in  New 
York  and  in  Canada.  These  leafless  marine  plants  are 
the  oldest  types  of  vegetation  known  to  have  existed. 

The  vegetable  kingdom  has  been  divided  into  six 
classes.  The  first  includes  the  seaweeds,  the  lowest  of 
vegetables;  the  second,  the  mosses  and  liverworts;  the 
third,  the  horse-tails,  the  ferns,  and  the  club-mosses;  the 
fourth,  the  cycads  and  the  firs ;  the  fifth,  the  pond-weeds, 
the  palms,  and  the  lily  tribe ;  and  the  sixth,  the  birch, 
walnut,  sycamore,  and  all  plants  having  seeds  with  two 
lobes. 

The  first  plants  that  make  their  appearance  belong  to 
the  first  class.  Seaweeds  alone  of  the  vegetable  king- 
dom are  found  below  the  highest  beds  of  the  Silurian 
formation.  Above  them  we  find  plants  of  the  second 
class ;  above  these,  plants  of  the  third  class,  which  include 
nearly  all  the  plants  of  the  carboniferous  period.  Above 
the  carboniferous,  cycads  and  conifers  become  abundant ; 
then  the  palms  make  their  appearance  ;  and,  lastly,  the 
plants  of  the  sixth  class,  which  constitute  the  vegetation 
of  the  existing  forests  in  the  temperate  zones 


88  LECTURES   ON  GEOLOGY. 

Above  the  Potsdam  sandstone  is  the  calciferous  sand- 
stone, so  called  because  its  beds  of  sandstone  contain 
lime ;  probably  owing  to  the  shells  embedded  in  them. 
It  generally  consists  of  thin  layers,  and  is  found  both 
south  and  north  of  the  Potsdam  region  in  the  State  of 
New  York,  and  in  Canada,  where  it  extends  from  Brock- 
ville  to  Ottawa,  and  sometimes  attains  a  thickness  of 
three  hundred  feet.  It  may  be  seen  in  Herkimer  County, 
New  York,  its  cavities  containing  very  beautiful  and 
perfect  crystals  of  quartz ;  and  on  the  Upper  Mississippi, 
where  it  forms  the  lower  magnesian  limestone.  In 
Missouri  and  Arkansas,  it  is  a  lead-bearing  rock;  and 
will,  I  have  no  doubt,  be  found,  when  deeper  explorations 
are  undertaken,  to  be  highly  so  in  the  great  lead-region 
of  the  North-west.  Occasionally,  anthracite  is  found  in 
it,  supposed  by  Professor  Hall  to  be  derived  from  the 
marine  plants  of  the  time  ;  but  probably  formed  from, 
petroleum  altered  by  the  heat,  to  which  the  rock  has 
subsequently  been  subjected.  I  have  seen  it  frequently 
in  rocks  of  this  age  in  Canada. 

The  calciferous  sandstone  contains  many  more  fossils 
than  the  Potsdam,  —  especially  the  upper  part  of  it.  The 
earth,  by  constant  radiation,  by  the  abstracting  power 
of  the  waters,  that  covered  nearly  its  whole  surface,  and 
by  its  numerous  volcanic  mouths,  was  parting  with  its 
heat  continually ;  and  conditions  for  life-existence  were 
therefore  constantly  improving.  Remains  of  sea-plants 
are  common  in  many  localities  :  they  probably  luxuriated 
in  thermal  waters  that  were  too  hot  for  animals,  though 
these  were  by  no  means  rare.  Mollusks  are  the  most 
numerous  of  those  preserved,  and  nearly  all  of  these  are 
gasteropods.  A  few  cephalopods  have  been  discovered; 
but  I  shall  treat  of  them  when  we  come  to  where  they 
were  larger  and  more  abundant. 


LECTURES   ON  GEOLOGY.  89 

In  European  beds  of  this  age,  fossils  that  are  similar, 
though  not  identical,  are  found ;  so  that  distinct  provinces 
of  life  existed  even  at  that  early  time. 

Above  the  calciferous  sandstone,  in  the  State  of  New 
York,  we  find  the  Chazy  limestone,  —  named  from  the 
town  of  Chazy,  in  Clinton  County,  New  York,  where  it  is 
found,  —  the  bird's-eye  limestone,  the  Black-river  lime- 
stone, and  the  Trenton  limestone.  In  the  State  of 
New  York,  these  are  all  distinct,  and  contain  charac- 
teristic fossils ;  but  in  no  other  state  or  country  have 
they  all  been  found.  They  may  all  be  classed  under  the 
head  of  Trenton  limestone,  one  of  the  most  widespread 
and  highly  fossiliferous  groups  of  rocks  found  in  the 
United  States.  It  receives  its  name  from  Trenton,  in 
Central  New  York,  where  the  West-Canada  Creek  falls 
over  rocks  belonging  to  this  group.  In  New  York,  it  is 
in  some  places  three  hundred  feet  thick,  but  swells  in 
the  neighborhood  of  Ottawa,  Can.,  to  the  thickness  of 
eight  hundred  feet.  There  is  a  wide  exposure  of  it  in 
Central  Tennessee,  where  it  is  about  three  hundred  feet 
thick ;  and  in  the  lead-region  of  the  Upper  Mississippi, 
most  of  the  lead  of  that  district  being  obtained  from  it. 
The  upper  part  of  the  Trenton  limestone  in  the  lead- 
region  is  styled  the  Galena  limestone  ;  having  a  thick- 
ness at  Galena  of  about  two  hundred  and  fifty  feet. 
This  rock  contains  a  considerable  amount  of  magnesia. 

The  limestones  of  the  Trenton  series  abound  with 
fossils.  On  some  of  the  slabs,  as  those  laid  down  for 
flagging  in  the  streets  of  Ottawa,  branching  seaweeds 
are  spread  over  their  surface ;  and  in  and  around  Cincin- 
nati, shells,  corals,  and  fragments  of  crinoids  and  trilo- 
bites,  may  be  seen  in  the  greatest  profusion. 

The  crinoid,  of  which  many  species  flourished  during 


90 


LECTURES   ON   GEOLOGY. 


the  Trenton  period,  was  a  radiate  with  a  root  like  a 
plant,  by  which  it  was  firmly  attached  to  the  rock. 
From  the  root,  a  long,  many-jointed  stem  arose,  and  sup- 
ported a  cup-like  body  containing  the  stomach :  around 
it  were  arms,  with  feathery  fingers  attached,  which 
spread  out  and  closed  at  the  will  of  the  animal,  forming 
a  kind  of  net,  in  which  the  -small  animals  were  en- 
trapped that  constituted  its  prey.  From  the  resem- 
blance of  some  species,  when  closed,  to  the  bud  of  a  lily, 
it  received  the  name  of  crinoid,  from  the  Greek  krinon, 
"  a  lily."  Fig.  3  represents  a  group  of  crinoids  as  they 

Fig.  3. 


Pentacriuus  Briareus. 


grew  at  the  sea-bottom,  though  belonging  to  a  species 
that  flourished  at  a  more  recent  period. 

Mollusks  were  unusually  abundant,  many  hundred 
different  forms  having  been  discovered ;  among  them  a 
variety  of  cephalopods,  now  very  rare,  but  then  ex- 
tremely abundant,  and  frequently  of  enormous  size. 
Cephalopods  are  the  largest  and  most  advanced  of  mol- 
lusks  in  organization.  They  have  a  large  head  armed 


LECTURES  ON  GEOLOGY.  9.1 

with  strong  jaws  like  a  parrot's  beak,  large  and  promi- 
nent eyes  placed  on  the  side  of  the  head,  and  a  large 
and  fleshy  tongue.  The  arms,  or  feet  (for  they  answer 
both  purposes),  are  generally  from  eight  to  ten,  and  pro- 
vided with  rows  of  suckers,  which  hold  so  firmly,  that  it  is 
easier  to  tear  the  limb  in  pieces  than  to  detach  it.  "  If 
they  once  touch  their  prey,  it  is  enough.  Neither  swift- 
ness nor  strength  can  avail.  The  shell  of  the  lobster  and 
crab  is  a  vain  protection ;  and  even  animals  many  times 
their  size  have  been  soon  disabled  in  their  powerful  and 
pertinacious  grasp." 

One  of  the  most  common  cephalopods  of  this  time  was 
the  ortlioceratite.  Its  name  means  literally  straight-horn, 
from  orthos,  Greek  for  "straight,"  and  keras,  "horn;" 
and  a  look  at  the  fossil  shows  at  once  the  propriety  of 
the  name.  It  was  a  long,  straight,  chambered  shell ; 
tapering  from  the  base,  where  the  largest  chamber  is, 
to  a  point.  As  many  as  seventy  chambers  have  been 
counted  in  one  shell:  they  were  filled  with  air,  and 
serVed  as  floats.  Through  all  these  chambers  passed  a 
tube  called  the  sjphuncle,  tapering  like  the  shell :  it 
thus  extended  from  the  living  animal  to  the  outermost 
chamber.  The  specific  gravity  of  the  shell  with  the 
enclosed  animal  was  less  than  that  of  the  water  :  hence 
it  could  only  sink  by  an  effort.  It  possessed  a  funnel, 
by  which  it  ejected  water  with  great  force,  and  thus 
reached  the  sea-bottom,  where  it  could  hold  by  its  long, 
muscular  arms.  When  it  wished  to  reach  the  surface,  all 
that  was  necessary  was  to  detach  itself;  and  the  light- 
ness of  the  shell  brought  jt  at  once  to  the  top.  The 
living  nautilus  of  the  Indian  Ocean  enables  us  best  to 
understand  these  extinct  forms ;  for,  though  the  nautilus 
is  coiled,  its  chambers  are  similar,  the  animal  passing 


92  LECTURES  ON  GEOLOGY. 

from  a  smaller  to  a  larger  one  as  its  increased  size 
demands  an  increase  in  the  size  of  its  tenement.  Pro- 
fessor Owen  found  the  crop  of  one  filled  with  fragments 
of  a  small  crab.  He  gives  the  following  passage  from 
an  old  Dutch  naturalist,  which  I  think  sheds  light  upon 
the  habits  of  the  orthoceratite  :  "  When  the  nautilus 
floats  on  the  water,  he  puts  out  his  head  and  all  his 
tentacles,  and  spreads  them  upon  the  water,  with  the 
poop  of  the  shell  above  water,  and  with  his  head  and 
tentacles  upon  the  ground,  making  a  tolerably  quick 
progress.  He  keeps  himself  chiefly  upon  the  ground, 
creeping  also,  sometimes,  into  the  nets  of  the  fishermen ; 
but  after  a  storm,  as  the  weather  becomes  calm,  they  are 
seen  in  troops,  floating  on  the  water,  being  driven  up  by 
the  agitation  of  the  waves.  This  sailing,  however,  is  not 
of  long  continuance ;  for,  having  taken  in  all  their  tenta- 
cles, they  upset  their  boat,  and  so  return  to  the  bottom.'- 
The  Trenton  period  was  that  in  which  the  orthocera- 
tites  attained  their  greatest  size.  I  have  seen  one, 
obtained  from  the  Trenton  limestone,  in  Galena,  111., 
eleven  inches  in  diameter  at  the  large  end  :  it  was  proba- 
bly twenty  feet  in  length.  The  accompanying  engraving 

Fig.  4. 


Orthoceras  Titan. 


(Fig.  4)  represents  an  orthoceratite  from  the  Trenton  lime- 
stone, Lowville,  N.Y. ;  and,  though  but  a  fragment,  the 
original  is  nearly  nine  feet  long,  and  the  large  chamber 
in  which  the  animil  lived  is  over  eight  inches  in  its 
largest  diameter.  What  enormous  tenants  must  have 


LECTURES   ON  GEOLOGY.  93 

inhabited  these  gigantic  shells! — their  long,  muscular 
arms  spread  out  to  seize  their  prey  as  they  ranged 
from  the  surface  to  the  twilight  depths  of  the  tepid 
ocean  in-which  they  swarmed.  The  orthoceratites  were 
carnivorous,  and  seem  to  have  been  to  the  Silurian  seas 
what  the  sharks  are  to  more  recent  ones.  Thus  early, 
at  least,  though  doubtless  long  before,  the  devourers 
were  busy.  Man  did  not  commence  the  work  of  kill- 
ing, as  some  have  supposed ;  for,  ages  before  he  had  a 
being,  the  existence  of  myriads  depended  upon  the 
destruction  of  others,  and  the  seas  were  dyed  with  the 
blood  of  the  victims.  Every  foot  of  ground  on  which 
we  tread  has  been  a  battle-field ;  and  more  blood  has 
been  shed  than  there  is  water  in  the  ocean.  It  is  well 
that  it  should  be  so.  Did  no  animals  exist  but  those 
that  feed  upon  vegetables,  as  much  life  would  be  possi- 
ble as  the  vegetation  of  the  globe  would  sustain.  The 
animals  had  all  died,  then,  of  disease  or  old  age :  now, 
these  all  live,  all  enjoy  existence,  and  perish,  without 
dreaming  of  the  fate  that  awaits  them  ;  but,  beside  them, 
an  infinite  number  that  feed  upon  them,  and  enjoy  exist- 
ence also, — their  enjoyment  being  so  much  more  than 
could  have  been  possible  in  any  other  way. 

It  is  difficult  for  those  unacquainted  with  geological 
investigations  to  conceive  of  the  multitudes  of  fossils 
that  are  found  in  the  limestones  of  the  Trenton  group. 
As  a  general  thing,  in  Cincinnati,  0.,  Ottawa,  Can.,  and 
Nashville,  Tenn.,  where' the  Trenton  limestone  is  found, 
you  cannot  pick  up  the  smallest  stone  without  discov- 
ing,  on  examination,  that  it  is  a  sepulchre  containing  a 
multitude  of  fossil  tenants, —  shells  crowded  into  shells; 
trilobites,  corals,  and  shells  broken  into  fragments,  and 
these  cemented  together  by  pressure  into  solid  rock; 
and,  of  the  rock  so  formed,  houses,  churches,  and  cities 


94  LECTURES   ON  GEOLOGY. 

built :  so  that,  could  the  animals  return  and  claim  what 
was  once  theirs,  away  would  fly,  like  a  magician's  palace, 
many  of  our  houses,  churches,  and  gorgeous  cities,  and 
an  abyss  be  opened  beneath  them  deeper  than  the  Lis- 
bon earthquake  made.  Well  did  Shelley  say,  "  The  dust 
we  tread  upon  was  once  alive."  In  many  parts  of  the 
country  this  is  a  sober  truth. 

rig.  5.  Trilobites    appear   in    this   lime- 

stone in  great  numbers,  and  more 
than  twenty  species  have  been  rec- 
ognized. Calymene  BlumenbacMi 
(Fig.  5)  is  from  Dudley,  England.  It 
is  one  of  the  species  having  a  wide 
range;  being  found,  in  the  United 
States,  from  the  base  of  the  Tren- 
ton limestone  to  the  top  of  the  Hud- 
son-river group. 

No  feet  of  trilobites  have  yet  been 
caiymene  BlumenbacMi.  discovered  ;  and,  since  they  have 
been  found  in  most  perfect  preservation,  it  seems  proba- 
ble, that,  if  they  had  possessed  feet,  we  should  before  this 
have  found  them.  It  is  probable  that  the  caudal  shield, 
or  tail-portion,  which  seems  to  have  been  movable  in  all 
of  them,  furnished  them,  acting  as  a  paddle,  with  the 
means  of  locomotion.  Thus  through  the  early  seas  they 
paddled  their  light  canoes,  and  set  a  worthy  example 
to  some  idle  people  of  the  present  time. 

Corals  are  very  numerous,  both  branching  and  massive. 
About  forty  species  have  been  described  ;  but  many  yet 
remain  to  be  described.  A  portion  of  a  mass  weighing 
fifteen  hundred  pounds,  from  the  Black-river  lime- 
stone, which  I  include  in  the  Trenton,  lying  immediately 
beneath  it,  is  now  in  the  New- York  State  Collection  at 
Albany.  "  There  is  no  reason/'  says  Hall,  "  why  extensive 


LECTURES   ON   GEOLOGY.  95 

coral-reefs  may  not  have  margined  our  early  shoals 
or  islands  of  granite,  as  those  of  modern  origin  do  the 
islands  and  shoals  of  our  present  seas."  I  have  no 
doubt  of  the  correctness  of  this  view:  the  masses  of  coral 
that  I  have  seen  in  the  Trenton  limestone  of  Central  Ten- 
nessee and  other  localities  bear  evidence  to  the  truth  of  it. 
Still  ascending,  we  arrive  at  the  Hudson-river  group, — 
an  enormous  mass  of  shales,  slates,  sandstones,  and,  in 
some  places,  limestones.  Deposits  in  Anticosti  Island, 
one  thousand  feet  in  thickness,  belong  to  this  group. 
It  is  exposed  through  the  Mohawk  Valley 
and  on  the  Hudson  River,  from  which  it 
takes  its  name.  Towards  the  West,  the  beds 
contain  more  lime,  and  fossils  are  more 
abundant.  They  resemble  those  of  the 
Trenton  period  in  the  West,  so  that  the 
two  can  hardly  be  separated.  Fie;.  6  repre- 

•^  Rhynchonella  incre- 

sents  a  brachiopod  from  the  Hudson-river 
group,  Iron  Ridge,  Wis.     It  is  found  abundantly  near 
Cincinnati,  Richmond,  Ind.,  and  many  other  localities. 
The  most  remarkable  fossils  of  this  period  are  grapto* 

Fig.  7. 


Graptolithus  octobrachiatus. 

lites  (Fig.  7),  of  which  there  is  a  large  variety.     The 


96  LECTURES   ON  GEOLOGY. 

Dame  of  the  one  figured  signifies  eight-armed  graptolite  : 
it  was  found  near  Quebec.  They  are  very  seldom  found  as 
perfect  as  this,  and  in  their  imperfect  state  gave  rise  to 
various  conjectures  of  their  nature.  At  one  time,  they 
were  considered  vegetables  ;  at  another,  slender  orthoce- 
ratites :  but  now  they  are  generally  regarded  as  radiate 
forms  belonging  to  the  acalephs,  or  sea-nettles.  The  two 
small  figures  represent  the  young  of  two  distinct  spe- 
cies. The  shales  of  the  Hudson  period  abound  with  the 
remains  of  these  singular  animals,  which  are  more  rare  in 
the  Devonian,  and  become  extinct  in  the  carboniferous ; 
no  remains  of  them  having  been  found  above  the  coal- 
measures.  Beds  in  England  of  about  the  same  age  as 
the  Hudson-river  group  also  abound  with  graptolites, 
which,  since  they  are  generally  found  in  shales,  seem  to 
have  thriven  best  in  a  muddy  ocean,  as  the  corals  throve 
best  in  a  clear  one. 

With  the  Hudson  period  closed  the  lower  Silurian. 
All  the  Silurian  rocks  above  this  are  termed  upper 
Silurian. 

The  Rocky-Mountain  range,  long  and  narrow,  existed 
at  this  time,  and  probably  long  before ;  but  between  that 
and  land  on  the  east  lay  a  wide  ocean,  at  the  bottom  of 
which  beds  of  immense  thickness  had  to  be  laid  as  a 
foundation  for  the  interior  of  the  continent.  Toward 
the  south,  the  land  was  extending;  and  a  considerable 
part  of  Northern  New  York  and  Western  Vermont  was 
out  of  the  water.  A  large  tract  of  high  land  existed  in 
the  Atlantic  Ocean,  the  sediment  from  which  made  many 
of  the  rocks  belonging  to  this  period,  that  are  found  on 
the  eastern  portion  of  this  continent. 

Mountain-ranges  were  heaved  again  and  again,  slowly 
sinking  in  consequence  of  the  thinness  of  the  earth's 


LECTURES   ON  GEOLOGY.  97 

crust;  rocks  were  overturned,  for  on  their  upturned 
edges  we  find  in  many  places  that  the  upper  Silurian 
beds  are  laid ;  immense  crevices  opened  at  the  sea- 
bottom,  and  closed  after  vomiting  fiery  torrents  ;  and  life 
over  wide  oceanic  areas  was  frequently  destroyed  and 
renewed.  By  unsteady  uplift,  the  land  so  increased  in 
the  north-eastern  part  of  the  United  States  and  South- 
eastern Canada,  that,  by  the  close  of  the  lower  Silurian 
period,  a  small  continent  had  been  formed,  over  which 
the  tenantless  waters  ran,  sweeping  calcareous  sediment 
from  the  newly-risen  land  into  the  undivided  sea. 

The  earth,  though  much  improved,  was  yet  rude  and 
unfinished.  The  continents  were  not ;  and  only  large 
islands  of  naked  rock,  wave-washed  and  rain-worn,  that 
sank  and  rose  obedient  to  disturbing  forces  within, 
indicated  the  places  where  they  should  be. 

The  atmosphere  was  still  heavy  with  impurities,  and 
hugged  closely  islands  and  sea.  The  night  was  probably 
utter  blackness,  and  the  day  but  a  diffusion  of  light. 

The  gray  dawn  appears  in  the  east,  and  gradually 
extends  itself  over  the  watery  waste.  One  by  one,  rocky 
islands  loom  up,  faintly  visible  above  the  dashing 
waves.  .  Seaweeds  of  varied  form  and  hue,  their  long, 
leafless  arms  interwoven,  rise  and  fall  with  the  passing 
waves.  Trilobites  by  millions,  like  water-beetles,  are 
sculling  their  tiny  boats  in  every  direction,  in  pursuit 
of  the  soft-bodied  animals  that  swarm  by  myriads  in 
these  more  than  tropical  waters.  Cephalopods,  larger 
than  a  man,  are  floating  on  the  waters,  or  diving  into  its 
depths  ;  their  long  arms  extended  to  catch  their  prey. 
Meadows  of  crjnoids  adorn  the  sea-bottom;  their  lily- 
like  bodies,  with  feathery  fringes,  more  beautiful  than 
tulip-cups,  while  their  many-jointed  stems  bend  to  the 


98  LECTURES   ON  GEOLOGY. 

moving  waters  like  grass  in  the  summer  breeze.  Here 
and  there,  coral-reefs  stretch  away  in  waves  of  beauty ; 
their  builders  busy  in  purifying  these  mineral  waters, 
arid  preparing  them  for  higher  beings  than  the  earth  has 
yet  beheld. 

We  walk  along  the  beach,  and  find  rows  of  shells  and 
broken  corals,  heaped  as  the  grass  that  has  fallen  before 
the  scythe  of  the  husbandman  ;  every  tide  bearing  new 
harvests  to  the  shore.  We  turn  to  the  land,  but  behold 
only  barren  rocks,  from  whose  heated  surface  vapor  is 
rising  in  continual  clouds.  Nothing  is  heard  save  the 
volcano's  roar  and  the  clash  of  the  angry  waves. 

The  thousands  of  feet  of  rock  that  we  know  were 
deposited  during  this  time  within  the  boundary  of  what 
is  now  the  United  States,  we  may  be  sure  took  a  long 
period  of  time  for  their  deposition  as  sediment,  especially 
when  we  remember  that  the  land-surface  of  the  globe 
was  small,  and  there  were  no  large  rivers. 

Many  of  the  great  metallic  deposits  of  North  America 
are  found  in  lower  Silurian  beds.  The  copper  and  gold 
of  Canada  East,  the  copper,  iron,  and  lead  of  Lake 
Superior,  the  gold  of  Nova  Scotia,  and  the  lead  of  Illinois, 
Wisconsin,  Iowa,  and  Missouri,  are  all  found  here.  Me- 
tallic deposits  are  generally  found  in  veins,  which  were 
once  fissures  or  crevices  in  the  rocks.  At  a  very  early 
period  in  the  world's  history,  there  were  no  veins;  for, 
when  the  earth's  crust  was  yielding,  there  could  be  no 
crevices,  and  consequently  no  veins  :  but  as  it  cooled, 
and  contracted  by  cooling,  ridging  up  into  hills  and 
mountains,  crevices  by  millions  must  have  been  formed 
by  the  rending  of  the  rocks.  Many  of  these  closed 
again,  leaving  nothing  but  a  line  to  tell  where  they 
existed ;  others  have  been  filled  with  clay  and  stones 


LECTURES   ON  GEOLOGY.  99 

swept  in  from  the  top,  and  sometimes  by  melted  rock 
forced  up  from  below ;  and,  in  these  cases,  we  have  no 
metallic  veins.  Of  those  in  which  metals  are  found,  some 
are  gash  veins,  which  are  shallow,  and  have  been  formed 
without  much  breaking  up  of  the  strata  with  which 
they  are  connected ;  others,  and  these  are  the  most  im- 
portant, are  true  veins,  fissures  in  the  earth,  of  indefinite 
length  and  depth,  sometimes  extending  for  several  miles, 
and  probably  going  down  to  the  molten  ocean :  no  mine 
has  yet  gone  to  the  bottom  of  one.  The  vein  is  not  a 
mass  of  ore  :  the  greater  part  of  it  is  generally  occupied 
by  some  rock,  different  from  the  strata  in  which  the 
vein  is  found,  and  known  by  the  name  of  gangue,  or  vein- 
stone. Quartz  is  most  commonly  the  mineral  found  in 
this  position. 

There   are    four  principal  ways  by  which  it  is  sup- 
posed these  metallic  veins  have  been  filled  :  — 

1.  Infiltration.  —  Water  heated  in  the  earth's  interior, 
and  rising  in  consequence,  as  heated  water  invariably 
does,  brings  up  with  it  the  minerals  and  metallic  ores 
which    it    holds   in   solution,   obtained    by    circulating 
through  deep  beds;  and,  as  it  cools,  deposits  them  on 
the  sides  of  the  crevice  through  which  it  flows,  as  lime 
is  deposited  from  calcareous  water  on  the  sides  of  the 
kettle  in  which  it  is  boiled.     I  have  seen  rock  nearly  an 
inch  thick  taken  out  of  an  engine-boiler,  deposited  from 
the  lime-water  that  had  been  boiled  in  it. 

2.  Segregation.  —  The    metal    having   been    diffused 
through  the  surrounding  rock  at  the  time  of  its  deposi- 
tion, it    has    been   segregated  from  it,  and  conveyed, 
probably  by  electric  agency,  into  the  crevices  traversing 
the  rock.     Most  of  the  gash  veins  seem  to  have  been 
filled  in  this  way. 


100  LECTURES   ON  GEOLOGY. 

3.  Injection.  —  From  the  internal  fluid  mass,  metals,  in 
a  state  effusion,  may  have  been  forced  through  crevices 
to  the  surface.  Sometimes  metals  come  up  with 
lava  in  volcanic  eruptions.  Veins  of  injection  are  found 
in  Lake  Superior,  where  copper  has  come  gurgling  up 
in  boiling  floods,  and  consolidated  in  masses  weighing 
hundreds  of  tons.  In  California  and  Nova  Scotia,  the 
gold  mixed  with  quartz  seerns  to  have  been  forced  up 
in  a  similar  manner ;  and,  as  an  evidence  of  its  original 
fluid  condition,  we  have  the  thick  veins  of  quartz  poor 
in  gold,  and  the  thin  ones  rich.  The  thick  ones,  cooling 
slowly,  allowed  the  gold  to  sink  back  again  by  virtue  of 
its  greater  weight ;  but  the  thin  ones,  cooling  rapidly, 
held  the  precious  article  in  their  grasp. 

Lastly,  Sublimation.  —  When  water  boils,  it  passes 
into  the  air  in  the  condition  of  steam,  or  vapor.  All 
metals,  when  subjected  to  sufficient  heat,  can  be  reduced 
in  like  manner  to  vapor.  Quicksilver  can  be  boiled  and 
dissipated  on  a  common  fire,  lead  and  zinc  in  a  furnace; 
and,  by  the  heat  of  the  compound  blow-pipe,  gold  can  be 
evaporated.  The  heat  in  the  interior  of  the  earth  is, 
without  doubt,  great  enough  to  drive  all  metals  into  this 
state ;  and,  when  crevices  have  been  made  deep  enough, 
the  vapor  has  risen  through  them,  and  condensed  upon 
their  sides  in  the  upper  part  where  cool,  and  produced 
bodies  of  ore  proportioned  to  the  size  of  the  crevice 
and  the  amount  of  vapor.  When  the  heat  from  below 
reached  rocks  containing  water,  this  water  near  the 
crevice  would  be  converted  into  steam,  and  the  steam 
would  modify  the  result ;  softening  the  rock,  and  trans- 
porting quartz  and  other  minerals  from  one  portion  of 
the  vein  to  another,  or  from  the  neighboring  rock  into 
the  vein.  Most  of  the  copper  in  Canada  seems  to  have 


LECTURES  ON  GEOLOGY.  101 

>oen  produced  in  this  way,  and  the  gold-bearing  ores 
of  Colorado.  The  vapor  of  iron,  coming  up,  has  united 
with  the  vapor  of  sulphur,  and  produced  sulphuret  of 
iron  ;  the  vapors  of  lead  and  sulphur,  uniting,  have  pro- 
duced sulphuret  of  lead  or  galena ;  and  in  a  similar 
way  the  sulphurets  of  zinc,  silver,  &c.,  have  been  formed. 
The  lead  found  in  Wisconsin,  Illinois,  and  Iowa,  in 
sheets  or  in  cubes,  lining  caves,  has,  I  have  no  doubt, 
been  placed  in  its  present  position  by  sublimation. 
Driven  from  below  by  heat  in  a  state  of  vapor,  it  has 
passed  through  the  underlying  porous  sandstone  to  the 
limestone,  in  whose  cavities  it  is  now  found.*  Galena 
placed  in  the  middle  of  a  tube,  and  highly  heated,  on 
having  steam  passed  through  it,  is  sublimed,  in  the 
colder  part  of  the  tube,  in  cubes  which  exactly  resemble 
the  ore.  Since  the  original  deposition  of  the  ore  by 
sublimation,  many  of  the  deposits  have  doubtless  been 
changed  by  infiltration  and  segregation ;  and  similar 
changes  are  still  going  on. 

The  fact  that  the  lead-region  of  the  North-west  is 
coincident  with  the  region  of  no-drift  seems  to  indicate 
the  heated  condition  of  the  rocks  during  the  drift 
period,  preventing  the  formation  of  ice,  and  its  passage 
from  the  north  ;  while  the  condition  of  the  rocks  and 
their  embedded  fossils  demonstrates  that  the  rocks  at 
some  period  have  been  intensely  heated. 

The  great  reservoirs  of  metallic  wealth  are  at  a  great 
depth  in  the  earth's  interior,  —  especially  the  heavier 
metals,  whose  greater  specific  gravity  has  carried  them 
do\\n;  and  probably  rich  mines  might  be  opened  any- 
where, if  men  could  sink  to  a  sufficient  depth,  and  the 
internal  heat  of  the  earth  would  permit  them  to  work. 

*  I  heard  this  idea  first  advanced  by  Dr.  Charles  T.  Jackson  of  Boston. 


102  LECTURES  ON  GEOLOGY. 

Although  we  find  metallic  deposits  in  lower  Silurian 
rocks,  it  must  not  be  inferred  that  all  we  find  in  them 
were  formed  during  that  period;  many  of  them  having 
bec-n  deposited  during  much  more  recent  times.  Nor 
would  it  be  correct  to  suppose  that  metallic  deposits  are 
confined  to  rocks  of  Silurian  age.  In  Colorado,  the 
metals  are  found  principally  in  metamorphic  rocks,  some 
in  granitic.  The  lead  of  England  occurs  in  the  moun- 
tain limestone  ;  and  copper  is  found,  in  Germany,  in  beds 
younger  still. 

In  some  places,  it  is  evident  that  ore-forming  processes 
are  operating  at  the  present  time.  Mr.  Wright  of  Liver- 
pool, England,  says,  "  I  opened  a  vein  that  had  riot  been 
worked  for  two  hundred  years,  and  from  which  the  ore 
had  been  well  cleaned  out.  I  found  that  -the  sides  of 
the  vein  had  been  replenished  with  the  carbonate  of  lead 
in  crystals  of  an  inch  in  length,  which,  no  practical  man 
can  doubt,  have  been  formed  since  the  period  when  the 
mine  was  worked." 

M.  Trebra,  director  of  the  mines  in  Hanover,  observed 
native  silver  and  vitreous  silver-ore  coating  the  wooden 
supports  left  in  a  mine  called  Dreyweiber,  in  the  district 
of  Marienburgh,  which  had  been  under  water  two  hun- 
dred years. 

Electric  currents  traverse  metallic  veins,  as  we  know 
by  experiment ;  and  these  are,  doubtless,  changing  the 
character  of  the  deposits  constantly.  We  may,  by 
calling  in  their  agency,  account  for  the  fact  that  veins 
are  poor  in  ce-rtain  portions  of  their  course  when 
traversing  certain  rocks,  but  become  rich  when  rocks 
of  a  different  nature  are  reached.  No  one  theory  can 
account  for  all  the  facts  observed  in  the  mines  with 
which  we  are  familiar. 

The  Hudson-river  group  is  covered  in  many  places 


LECTURES  ON  GEOLOGY.  103 

b}r  a  bed  of  conglomerate,  made  up  of  coarse  sand  and 
rounded  pebbles  of  quartz.  It  is  called  the  Oneida 
conglomerate,  and  is  the  lowest  deposit  of  the  upper 
Silurian.  But  a  few  feet  in  thickness  in  some  places,  it 
swells  to  several  hundred  feet  on  the  Hudson  River. 
With  the  exception  of  some  obscure  fucoidal  impres- 
sions, it  is  destitute  of  fossils,  as  might  be  expected 
from  the  coarseness  of  its  composition  and  the  agitation 
of  the  water  in  which  it  was  deposited. 

The  Medina  sandstone  overlies  this,  and  consists  of 
beds  of  shale  and  sandstone,  varying  in  color  from  a 
deep  red  to  light  gray  ;  this  being  their  color  at  Lock- 
port,  N.Y.,  where  they  are  quarried,  and  used  extensively 
for  flagging  and  for  building  purposes.  There  are  but 
few  fossils  in  it ;  the  most  abundant  being  fucoids.  At 
the  top  of  the  Medina  sandstone  at  Jordan,  Can.,  I 
have  seen  slabs  of  sandstone  covered  with  their  branch- 
ing arms,  interwoven  in  every  direction,  and  as  perfectly 
sculptured  on  the  solid  rock  as  ever  were  figures  on 
marble  slab  by  the  sculptor's  cunning  hand. 

Some  species  of  shells  which  are  found  as  low  as  the 
Trenton  limestone  have  been  discovered  in  this.  There 
have  been  no  such  wholesale  destructions  and  creations 
as  some  geologists  have  fancied.  One  by  one,  old  forms 
have  perished,  and  new  ones  have  made  their  appear- 
ance, until  we  have  at  length  an  entirely  new  set  of 
organic  forms.  Thus  Professor  Owen,  whose  opinion  on 
this  subject  may  be  taken  as  that  of  our  best  geologists, 
says,  u  It  is  most  probable  that  the  extinction  of  specios, 
prior  to  man's  presence  or  existence,  has  been  due  to 
ordinary  causes,  —  ordinary  in  the  sense  of  agreement 
with  the  laws  of  never-ending  mutation  of  the  geographi- 
cal and  climatal  conditions  on  the  earth's  surface."  Par- 
tial destructions,  sometimes  over  broad  areas,  have 


104  LECTURES  ON  GEOLOGY. 

frequently  taken  place  in  the  past  turbulent  hisfory  of 
the  earth  ;  but,  as  we  become  familiar  with  wider  geo- 
logical  fields  we  find  the  range  of  certain  species,  once 
supposed  to  be  restricted  to  very  narrow  boundaries, 
much  extended. 

Above  the  Medina  sandstone  occur  beds  of  limestone, 
sandstone,  and  shale,  known  as  the  Clinton  group.  They 
abound  in  shells,  impressions  of  sea-plants,  and  tracks  of 
shell-fish  and  crustaceans  that  passed  over  the  soft  sand, 
which,  on  hardening  into  solid  sandstone,  retains  an 
enduring  impress.  One  of  the  most  important  shells 
found  in  them  is  a  large  brachiopod  called  pentamerus, 
Fig.  s.  one  species  of  which  is  represented  in 

§Fig.  8,  which   is   a   cast   of   the    interior, 
and  is  from  the  Clinton  Group,  Milwaukie, 
Wis.      Pentamerus    means  five -parted:    a 
look  at  the  figure  will  show  the  propriety 
of  the  name.     It  is  a  very'abundant  fossil  in 
rocks  of  this  age,  both  in  Europe  and  Ameri- 
pentamerasobiongu,.  ca<     Twenty  species  are   known.     At  Yel- 
low   Springs  and  Springfield,  in   Ohio,  and  at   Delphi, 
Ind.,  they  are  so  abundant,  that  a  block  can  hardly  be 
found  in  some  of  the  quarries,  destitute  of  their  impres- 
sions. 

Although  these  rocks  are  not  more  than  two  hundred 
feet  in  thickness  in  New  York,  in  Pennsylvania  they  are 
in  some  places  two  thousand  feet. 

From  Nova  Scotia  to  Tennessee  a  deposit  of  iron-ore 
is  found  in  connection  with  it,  which  has  a  thickness,  in 
some  places,  of  thirty  or  forty  feet.  This  ore  is  some- 
times called  lenticular  iron-ore,  and  at  others  fossil  iron- 
ore,  from  the  great  abundance  of  fossils  embedded  in  it. 
In  Ter.nessee,  where  it  occurs  in  beds  of  great  thickness 
and  excellent  quality,  it  is  called  dye-stone ;  being  used 


LECTURES   ON   GEOLOGY.  105 

extensively  by  the  inhabitants  in  dyeing  cloth.  Situated, 
as  it  frequently  is  there,  in  the  immediate  vicinity  of  coal- 
beds,  it  must  become  of  great  value  in  the  production  of 
iron. 

That  solid  limestone  rock,  eighty-five  feet  thick,  over 
which  Niagara's  waters  pour,  and  the  shale  beneath  it, 
eighty  feet  thick,  belong  to  the  Niagara  group.  As  th.o 
soft  shale  wears  away,  the  limestone  is  left  projecting, 
which  makes  that  covered  way,  behind  the  descending 
sheet  of  water,  along  which  visitors  pass. 

This  group,  consisting  of  shales  and  limestones, 
abounding  with  fossil  remains,  is  about  two  hundred 
feet  thick  near  Niagara  Falls,  but  is  said  to  attain  in 
Pennsylvania  a  thickness  of  fifteen  hundred  feet. 

The  fossils  consist  of  a  great  variety  of  corals  ;  one  of 
the  most  remarkable  and  characteristic  being  a  chain 
coral,  in  which  the  ends  of  the  tubes  look  like  the  chain 
stitch.  Several  species  of  beautiful  crinoids,  of  which 
about  thirty  species  are  known  in  this  group,  many 
trilobites,  and  shells  in  great  variety,  are  found  in  it. 

The  locks  at  Lockport,   N.Y.,  are  excavated  in  the 
Niagara  limestone  ;  and  its  fossils  have  been  found,  and 
may  still  be  found  there,  in  great  abun-         Fig.  9. 
dance.      Dalmania  limulurus   (Fig.  9)  is 
one  of  the  most  common  trilobites,  and 
is   frequently  found  as   perfect   as    here 
represented. 

This  group  has  been  traced  by  its  pecu- 
liar fossils  over  a  large  part  of  the  United 
States  and  British  America,  —  even  as  far 
north  as  the  arctic  region ;  indicating  the 
great  extent  and  uniform  condition  of  the 

-..,.        Tn     r  ^         I.L  Dalmania  limulurus. 

ocean  in  which  its  life-forms  dwelt. 


106  LECTURES  ON  GEOLOGY. 

At  Lockport,  N.Y.,  there  is  a  thick  bed  of  limestone 
belonging  to  this  group,  which  is  almost  entirely  com- 
posed of  remains  of  crinoids.  It  is  known  there  by  the 
name  of  Lockport  granite ;  the  crystals  in  granite  being 
represented  by  the  crinoidal  fragments.  The  Niagara 
limestone  contains  numerous  cavities  lined  with  crystals 
of  various  minerals,  —  calcareous  spar,  strontian,  selenite, 
fluor-spar,  and  many  others.  Most  of  these  cavities 
seem  to  have  been  occupied  by  fossils,  which,  on  decay- 
ing, have  left  the  space  to  be  occupied  by  these  miner- 
als, which  have  been  segregated  from  the  surrounding 
rock.  In  digging  the  canal  at  Lockport,  thousands  of 
beautiful  specimens  of  crystallized  minerals  were  taken 
out  of  this  rock. 

The  remaining  groups  of  the  Silurian  formation  recog- 
nized by  the  New- York  geologists  are  the  Onondaga 
salt  group  and  the  lower  Heldefberg  limestone.  The 
Onondaga  group  derives  its  name  from  the  Onondaga 
Lake,  near  Syracuse,  N.Y.,  in  the  vicinity  of  which  its 
limestones,  marls,  and  shales  are  found ;  and  from  the 
salt  which  is  found  in  brine  springs  and  wells  bored  in 
them.  In  the  upheaval  of  the  continent,  large  basins 
or  inland  seas  appear  to  have  been  left  filled  with  sea- 
water  ;  and  these,  becoming  more  salt  by  evaporation, 
must  have  been  extremely  unfavorable  to  life,  since  in 
the  rocks  deposited  during  this  time  fossils  are  very 
rare  :  indeed,  in  the  true  salt-bearing  beds,  they  are 
almost  unknown.  The  beds  of  this  group  are  believed 
to  extend  through  Canada  West,  and  form  a  part  of  the 
Island  of  Mackinaw. 

The  salt  found  in  these  rocks  is  never  in  a  solid  form, 
but  exists  in  brine,  which  is  pumped  up  from  depths 
varying  from  one  hundred  and  fifty  to  three  hundred 


LECTURES  ON  GEOLOGY.  107 

and  fifty  feet.  About  forty  gallons  of  the  water  fur- 
nish one  bushel  of  salt.  Nine  million  bushels  of  salt 
are  made  from  this  brine  every  year  in  Syracuse  and  its 
immediate  neighborhood,  with  no  apparent  diminution 
of  the  supply.  The  saliferous  beds  of  New  York  are 
about  a  thousand  feet  thick,  showing  the  continuance  of 
salt  lakes  or  inland  seas  for  long  periods  j  small  streams 
meanwhile  carrying  down  mud,  and  this  becoming  thor- 
oughly impregnated  by  the  saline  waters. 

The  Helderberg  limestone  receives  its  name  from  the 
Helderberg  Mountains,  in  Albany  County,  New  York; 
where  it  is  two  hundred  feet  thick.  It  has  been  found  in 
Pennsylvania,  Virginia  (where  it  is  eight  hundred  feet 
thick),  and  Tennessee.  At  the  base  of  this  group  lie 
beds  of  dark,  fine-grained  limestone,  some  of  which  are 
made  into  hydraulic  cement :  hence  the  name  given  to 
the  whole,  —  the  water-lime  group,  —  which  is  well 
developed  at  Williamsville,  near  Buffalo,  N.Y.  They 
contain  several  species  of  large  crustaceans  known  by 
the  names  of  eurypterus  (broad  fin)  and  pterygotus 
(wing-ear),  supposed  to  be  allied  to  the  limulus,  or 
common  horse-shoe  crab.  The  eurypterus  has  a  semi- 
circular head,  a  long,  jointed  body,  and  a  spiny  tail ; 
having  one  of  its  pairs  of  feet  flattened  into  broad  blades, 
or  oars  (whence  its  name),  probably  used  for  swimming. 
Similar  forms  are  found  in  beds  of  Great  Britain  belong- 
ing to  about  the  same  period. 

In  tl}e  lower  Helderberg  group,  about  four  hundred 
species  of  fossils  have  been  recognized,  many  of  them 
related  to  species  of  the  Niagara  period.  Conditions 
seem  to  have  been  pre-eminently  favorable  for  life  ;  as 
much  so  as  during  the  Trenton  and  Niagara  periods. 

Westward,  the  rocks  of  this  group  thin  out,  so  that 


108  LECTURES  ON  GEOLOGY. 

/ 

west  of  Oneida  County,  in  New  York,  they  are  hardly 
known,  but,  south,  are  readily  recognized  by  their  char- 
acteristic fossils  in  Pennsylvania,  Maryland,  Virginia, 
and  Tennessee. 

It  must  not  be  supposed  that  the  groups  thus  dis- 
covered and  marked  by  the  American  geologists  are  to 
be  found  the  world  over.  While  conditions  were  favor- 
able in  one  portion  of  the  Silurian  ocean  for  the  deposi- 
tion of  sandy  sediment,  in  other  portions  they  were 
favorable  for  the  deposition  of  clay ;  while  in  others, 
shells  and  corals  were  so  abundant,  that  limestone  formed 
from  them  was  laid  down.  Conditions  thus  different,  life 
was  necessarily  different. 

Thus  Professor  Hall,  speaking  of  the  trilobites  of  the 
early  periods,  says,  "  All  those  forms  requiring  calcareous 
(limy)  sediment  for  their  full  development  will  flourish 
during  the  deposition  of  such  material,  but  become  di- 
minished or  entirely  exterminated  when  a  change  to  ar- 
gillaceous (clayey)  or  arenaceous  (sandy)  deposits  takes 
place :  on  the  other  hand,  those  forms  which  require  a 
very  small  proportion  of  calcareous  matter,  and  flourish 
in  the  argillaceous  mud,  are  diminished,  or  cease  alto- 
gether, when  a  calcareous  deposition  supervenes.  The 
forms  which  maintain  a  bare  existence,  through  a  series 
of  calcareous  deposits,  become  extensively  developed  so 
soon  as  the  nature  of  the  sediment  changes ;  and  the 
same  may  be  said  of  those  requiring  calcareous  sediment 
during  a  period  of  argillaceous  deposits." 

So  the  beds  differ  much  in  thickness  in  different 
localities.  A  bed  that  in  one  place  is  five  hundred  feet 
thick,  fifty  miles  off  may  thin  out  to  twenty  feet. 
Where  it  is  five  hundred  feet  thick,  sediment  may 
have  been  rapidly  poured  in  from  some  river ;  and, 


LECTURES  ON  GEOLOGY.  109 

where  it  is  thin,  the  distance  may  have  been  too  great 
for  a  rapid  deposition. 

Geologists  are  not  able  to  run  exact  lines  of  division 
between  the  various  Silurian  groups,  that  shall  continue 
into  other  continents ;  for,  even  at  that  early  period, 
life-conditions  and  life-forms,  though  much  more  alike 
than  at  the  present  time,  were  sufficiently  diversified  to 
render  this  impossible. 

In  the  highest  of  the  upper  Silurian  beds  of  England 
and  Bohemia  have  been  found  a  few  relics  of  fishes, 
and  what  are  supposed  to  be  seeds  of  club-mosses, —  the 
first  traces  of  land-plants.  These  early  fishes  appear  to 
have  been  small,  but  extremely  carnivorous.  They  had 
no  true  bony  skeleton,  but  a  cartilaginous  or  gristly  one 
in  its  place  ;  and  belonged  to  the  orders  Placoid  and 
Ganoid. 

All  fishes  have  been  divided  by  Agassiz,  according  to 
their  scales,  into  four  orders,  —  placoid,  ganoid,  ctenoid, 
and  cycloid ;  a  division  which,  since  it  is  based  upon 
that  part  of  the  fish  most  frequently  preserved  in  a  fossil 
condition,  is  of  considerable  use  to  the  geologist. 

Placoid  is  from  the  Greek  plax,  "a  broad  plate  ;"  and 
it  includes  those  fishes  which  have  the  skin  irregularly 
covered  with  plates  of  enamel, —  sometimes  large,  and 
sometimes  reduced  to  small  points,  as  in  the  sharks. 
Their  prepared  skins,  known  by  the  name  of  shagreen, 
are  familiar  to  most  persons. 

Ganoid  is  derived  from  the  Greek  ganos,  "splendor;" 
and  the  fishes  belonging  to  this  order  are  covered  regu- 
larly with  angular  scales,  composed  of  horny  or  bony 
plates  coated  with  bright  enamel.  The  gar-pike,  so 
common  in  some  of  the  Western  rivers,  is  a  fine  speci- 
men of  the  ganoid :  the  scales  lie  in  regular  rows  over 


110  LECTURES  ON  GEOLOGY. 

the  whole  body,  and  overlap  one  another  like  the  shin- 
gles on  a  house. 

Ctenoid,  from  cteis,  "a  comb,"  includes  all  fishes  whose 
scales  are  toothed  at  the  margin,  as  in  the  perch.  The 
cycloid,  from  kuldos,  "  a  circle  :  "  the  fishes  of  this  order 
have  scales  smooth  on  the  margin,  and  often  ornamented, 
as  in  the  herring  and  salmon. 

The  placoids  and  ganoids  flourished  for  immense 
periods  before  the  ctenoids  and  cycloids,  which  include 
most  of  our  modern  fishes,  had  any  existence. 

By  the  close  of  the  Silurian  period,  great  advance  has 
been  made  in  every  direction :  the  land  areas  of  the 
globe  are  greatly  enlarged  ;  islands  and  shallow  seas 
show  where  continents  are  destined  to  be  ;  fishes  ap- 
pear in  the  ocean,  which  contains  many  varied  forms 
of  life ;  humble  land-plants  clothe  the  naked  rocks ;  the 
water  is  cooler,  the  air  purer,  volcanic  agency  less  vio- 
lent, and  the  world  prepared  for  higher  life-forms. 


DEVONIAN  PERIOD. 

AGE    OF   FISH. 

This  period  derives  its  name  from  Devonshire,  a  coun- 
ty in  England,  where  the  rocks  of  this  age  are  well 
represented.  In  Scotland  are  immense  beds  of  red 
sandstone  belonging  to  this  age,  and  known  as  the  Old 
Red  Sandstone,  which  attains  occasionally  a  thickness 
of  ten  thousand  feet. 

In  the  United  States,  the  rocks  of  this  period  have 
been  divided  into  several  groups,  being  composed  of 
varied  rocks,  each  containing  characteristic  fossils  which 
enable  the  geologist  to  distinguish  them  from  all  others. 


LECTURES  ON  GEOLOGY.  Ill 

The  following  are  the  groups  of  the  Devonian  rocks,  in 
descending  order,  as  recognized  by  American  geolo- 
gists:— 

CHEMUNG  GROUP. 
PORTAGE  GROUP. 
HAMILTON  GROUP. 
UPPER  HELDERBERG  GROUP. 
ORISKANY  SANDSTONE. 

There  is  probably  no  part  of  the  United  States  where 
they  can  be  as  well  studied  as  in  the  State  of  New 
York;  and  most  of  the  groups  take  their  names  from 
places  in  that  State  where  they  are  exposed.  The 
smaller  groups,  unknown  out  of  the  State  of  New  York, 
I  shall  not  notice. 

The  Oriskany  sandstone  derives  its  name  from  Oris- 
kany  Falls,  in  the  State  of  New  York,  where  it  is  twenty 
feet  thick.  In  Pennsylvania,  it  is  about  two  hundred  feet 
thick,  an.d  extends  into  Maryland  and  Virginia.  There 
are  many  fossils  in  it,  especially  brachiopods,  some  con- 
chifers,  cephalopods,  and  trilobites.  In  some  parts  of 
Virginia  and  Maryland,  perfect  fossils  are  found  in  it  in 
vast  numbers.  Many  of  the  fossils  are  casts,  and  are 
mistaken  for  "  butterflies,."  "petrified  hickory-nuts,"  &c. 

The  upper  Helderberg  group  consists  of  slates  and 
limestones,  principally  represented  in  the  West  by  lime- 
stones, which  are  more  than  three  hundred  feet  thick  in 
Michigan,  but  thin  out  in  Iowa  to  fifty  feet. 

The  upper  portion  of  the  group  is  called  the  cornifer- 
ous  limestone,  which  derives  its  name  from  the  beds 
and  nodules  of  flint  or  hornstone  which  are  found  in  it. 
cornu  being  the  Latin  word  for  "  horn."  It  is  usually  from 


112  LECTURES  ON  GEOLOGY. 

thirty  to  fifty  feet  Uiick,  and  contains  numerous  fossils, 
The  period  of  its  deposition  was  an  age  of  crowding 
crinoids  and  spreading  coral-reefs.  The  bottoms  of  the 
shallow,  warm,  calm  seas,  were  tenanted  by  myriads  of 
busy  workers ;  and  their  products  lie  spread  over  im- 
mense territories.  Professor  Hall  says,  speaking  of  this 
time,  "  With  the  advent  of  the  fishes  at  this  period,  we 
find  that  there  is  a  remarkable  accession  of  corals ;  and 
the  variety  of  form,  and  the  number  and  size  of  species, 
is  much  greater  than  at  any  preceding  period.  We  may 
follow  the  outcrop  of  this  formation,  bearing  in  many 
places  the  aspect  of  a  coral-reef,  along  a  line  of  more 
than  fifteen  hundred  miles."  In  the  neighborhood  of 
Geneva,  N.Y.,  acres  of  this  limestone  lie  bare  j  and  we 
can  walk  over  the  surface,  and  tread  under  our  feet 
millions  of  shells,  corals,  and  crinoids  of  this  interest- 
ing time.  The  earliest  fish  remains  yet  discovered  in 
America  are  from  the  Schoharie  grit  in  the  upper  Hel- 
derberg  group. 

At  the  Falls  of  the  Ohio,  near  Louisville,  Ky.,  the  river 
flows  over  a  corniferous  limestone  bed,  abounding  with 
corals,  crinoids,  trilobites,  and  fish  bones  and  scales. 
Some  of  these  are  of  large  size,  indicating  gigantic  bony- 
scaled  fish  in  these  ancient,  coral-bearing  seas.  The  frag* 
ments  of  fish-bones  in  the  white  limestone  look  much 
like  pieces  of  charcoal.  The  Devonian  period  has  been 
termed  the  age  of  fish,  from  the  great  abundance  of 
their  remains  that  has  been  found  in  its  beds. 

The  Rev.  John  Anderson  says,  "The  remains  of  these 
fishes  (ganoids)  are  so  very  abundant  in  the  yellow 
sandstone  deposit  of  Dura  Den,  Scotland,  that  a  space  of 
little  more  than  three  square  yards,  when  the  writer  was 
present,  yieldsd  about  a  thousand  fishes  j  most  of  them 


.ECTURES   ON   GEOLOGY. 

perfect  in  their  outline,  the  scales  and  fins  quite  entire, 
and  the  forms  of  the  creatures  often  starting  freely  out 
of  their  hard,  stony  matrix  in  their  complete  armature 
of  scale,  fin.  and  bone." 

These  remains  are  not  as  abundant,  however,  in  the 
Devonian  beds  of  the  United  States,  as  they  are  in  those 
of  Great  Britain  ;  nor  are  their  remains  as  well  preserved. 
Many  remarkable  fishes  belonging  to  this  period  are 
now,  thanks  to  the  labors  of  Hugh  Miller  and  others^ 
well  known.  The  pterichtliys,  or  winged  fish,  of  which 
eight  species  have  been  described,  was  a  ganoid  cased 
in  strong  armor,  weaker,  however,  beneath ;  and  in  this 
respect  it  resembled  our  iron-clads,  and  probably  for  the 
same  reason,  —  that  strength  was  most  needed  where 
the  blows  of  the  adversary  were  most  likely  to  come. 
"  It  has  less  resemblance  than  any  other  fossil  of  the  old 
red  sandstone  to  any  thing  that  now  exists,'  says  Agassiz. 
Its  wing-like  appendages  were  probably  used  for  weap- 
ons of  defence.  This  was  but  a  small  fish.  PtericJithys 
Milleri  is  little  more  than  an  inch  long.  • 

Another  fish  found'  in  the  same  beds,  somewhat  re- 
sembling the  pterichthys,  is  the  cephalaspis,  or  buckler- 
head,  as  its  name  signifies. 

Its  head  resembles  a  saddler's  knife,  as  Owen  ob- 
serves ;  and  the  animal  was  at  first  mistaken  for  a 
trilobite,  some  species  of  which  it  is  somewhat  like. 

The  coccosteus,  or  berry -bone,  as  its  name  means, 
was  so  called  on  account  of  the  berry-like  projections 
which  ornament  its  buckler-plates.  This  ornamentation 
so  much  resembles  that  on  the  buckler-plates  of  some 
tortoises,  that  it  led  to  the  belief  that  tortoises  existed 
in  Devonian  times.  The  jaws  and  teeth  of  this  fish  are 
particularly  interesting ;  the  teeth  being  chiselled,  as  it 


114  LECTURES  ON  GEOLOGY. 

were,  out  of  the  solid  bone  of  the  jaw,  just  as  the  teeth 
of  a  saw  are  cut  out  of  a  plate  of  steel. 

The  asterolepis,  or  star-scale,  was  a  bony-scaled  fish, 
that  sometimes  attained  a  length  of  twenty  feet ;  so  that 
the  Devonian  oceans  were  supplied  with  fishes  of  re- 
spectable size. 

Fig.  10. 


Holoptychius  uoblissimus. 

Another  fish  of  this  age  was  the  lioloptychius  (whole 
fold).  Fig.  10  represents  one  found  in  the  old  red 
sandstone,  at  Clashbinnie,  Scotland.  It  lies  on  its  back. 
"  The  body  "  (sa}rs  Hugh  Miller)  "  measures  a  foot  across 
by  two  feet  and  a  half  in  length,  exclusive  of  the  tail, 
which  is  wanting ;  but  the  armor  in  which  it  is  cased 
might  have  served  a  crocodile  or  alligator  of  five  times 
the  size."  The  jaws  are  armed  with  enormous  teeth, 
and  the  scales  are  very  large  and  deeply  wrinkled. 

Returning  to  a  consideration  of  America,  we  find 
above  the  corniferous  limestone  the  Hamilton  group ; 
a  series  of  shales  and  limestones  abounding  with  fossil 
remains  of  shells,  corals,  crinoids,  trilobites,  and  occa- 
sionally of  fishes  and  plants,  and  generally  in  an  excel- 
lent state  of  preservation:  for  they  were  buried  in 
tenacious  mud  at  the  sea-bottom,  which  hardened  into 


LECTURES  ON  GEOLOGY.  115 

shale ;  and  this,  when  exposed  to  the  atmosphere, 
returning  tt  mud,  the  fossils  are  easily  washed  out  by 
streams,  or  may  be  picked  out  as  perfect  as  shells  on  a 
modern  beach. 

The  Hamilton  group  extends  through  New  York,  a 
part  of  Pennsylvania,  Ohio,  Canada  West,  and  Michigan ; 
and  is  in  some  places  from  eight  hundred  to  one  thou- 
sand feet  in  thickness.  In  some  places,  I  have  seen  beds 
of  cell  coral  in  Hamilton  limestones,  the  cells  of  which 
were  filled  with  petroleum,  or  rock-oil. 

Every  one  has  heard  about  the  remarkable  discoveries 
of  oil  that  have  recently  been  made  in  the  earth's  inte- 
rior; and  most  persons  suppose  that  it  is  an  entirely 
new  thing  in  the  world's  history.  Indeed,  I  have  had 
persons  very  gravely  ask  me  if  I  did  not  suppose  that 
it  was  an  entirely  new  creation,  made  expressly,  in 
consideration  of  the  lack  of  fuel,  to  supply  the  world's 
increasing  necessities.  This  rock-oil  is,  however,  no 
new  thing.  We  read  in  the  Bible  about  the  rock  pour- 
ing out  rivers  of  oil ;  and  there  is  little  doubt  that  the 
Syrians  were  familiar  with  some  oil-springs  flowing  in 
their  day,  as  one  now  flows  at  Zante  which  was  referred 
to  by  Herodotus  twentj^-three  hundred  years  ago.  The 
Egyptians,  at  a  very  early  period,  used  asphaltum  for 
the  purpose  of  embalming  the  bodies  of  the  poor,  whose 
friends  could  not  afford  the  costly  spices  by  which  the 
bodies  of  the  more  wealthy  were  preserved.  This 
asphaltum  indicates  the  existence  of  petroleum  in  the 
neighborhood  ;  for,  when  the  volatile  portions  of  petro- 
leum pass  into  the  air,  the  thick,  black  residuum  is 
asphaltum.  The  Dead  Sea  is  sometimes  called  Lake 
Asphaltites,  from  the  asphaltum  found  floating  on  its 
waters  or  cast  upon  its  shore.  The  ancient  Babylonians 


116  LECTURES  ON  GEOLOGY. 

obtained  their  cement  from  the  fountains  of  Is  (now 
Hit),  on  the  right  bank  of  the  Euphrates,  where  it  still 
flows,  mingled  with  saline  and  sulphurous  waters. 
When  these  oleaginous  deposits  are  developed,  the 
Arabs  will  see  a  greater  excitement  in  the  Valley  of 
the  Euj  hrates  than  Layard  produced  when  digging  in 
the  ruins  of  ancient  Babylon. 

Soon  after  the  discovery  of  oil  near  Titusville,  in 
Western  Pennsylvania,  I  saw  many  pits  in  that  neigh- 
borhood that  had  been  dug  by  the  Indians  to  obtain 
petroleum,  which  was  used  by  them  to  paint  their 
bodies,  and  sometimes,  probably,  in  religious  ceremonies. 

At  Rangoon,  in  the  Burman  Empire,  wells  have  been 
sunk  from  two  hundred  to  five  hundred  feet  deep, 
which  yield  more  than  a  million  barrels  annually.  Oil 
has  been  taken  from  them  for  a  hundred  and  fifty  years. 

This  is,  then,  no  new  thing;  but  whence  comes  it? 
And  in  answer  to  this  question  we  have  many  theories, 
some  of  them  sufficiently  ludicrous.  One  suggests,  that, 
since  the  earth  is  a  huge  animal,  the  rocks  its  bones, 
the  water  circulating  in  them  its  blood,  the  grass  and 
trees  its  hair,  the  hills  pimples  upon  its  face,  and  ^Etna 
and  Vesuvius  eruptive  boils,  all  that  is  necessary  to 
obtain  oil  is  to  bore  through  the  skin  into  the  blubber 
of  the  monster,  and  oil  very  naturally  flows  from  it. 
Another  supposes,  that,  during  the  time  of  the  Flood,  the 
great  whales  were  buried  deep  under  accumulations  of 
mud,  in  those  places  where  the  oil  most  abounds ;  and 
hence  petroleum  is  merely  antediluvian  whale-oil.  It 
has  been  suggested,  that,  since  the  earth  is  at  some 
period  to  be  destroyed  by  fire,  the  oil  was  probably 
prepared  against  that  terrible  day  when  the  match  will 
be  applied,  and  the  world  burned  up. 


LECTURES  ON  GEOLOGY.  117 

Apart  from  these  ludicrous  explanations,  however, 
men  of  science  have  considered  this  question,  and  ren- 
dered their  verdict.  Professor  Silliman  says  that  "  petro- 
leum is  uniformly  regarded  as  a  product  of  vegetable 
decomposition."  Professor  Dana  says,  "  Petroleum  is  a 
bituminous  liquid  resulting  from  the  decomposition  of 
marine  or  land  plants  (mainly  the  latter),  and  perhaps, 
also,  of  some  non-nitrogenous  animal  tissues."  By  many, 
it  is  supposed  to  be  a  product  of  coal ;  and  hence  the 
name  of  "  coal-oil,"  so  frequently  applied  to  it.  Some 
suppose  that  the  coal,  being  subjected  to  the  enormous 
pressure  of  the  overlying  beds,  has  yielded  oil,  as  a 
linseed-cake  does  under  a  hydraulic  press ;  and  I  have 
seen  the  theory  advanced,  that  the  coal,  heated  (as  it 
evidently  has  been  in  the  coal-regions  of  Eastern  Penn- 
sylvania), gave  off  oily  vapors,  which,  rising  to  the  cold 
region  of  the  upper  air,  condensed,  and  subsequently 
fell  in  oily  showers,  making  its  way  as  best  it  could  to 
the  hollows  of  the  earth's  interior,  where  the  oil-borer 
finds  it  to-day. 

Facts  play  sad  havoc  with  these  various  theories. 
If  the  oil  comes  from  coal,  it  seems  strange  that  it  is 
so  rarely  met  with  in  a  coal-district.  I  have  visited 
coal-mines  in  England,  Wales,  Nova  Scotia,  Cape  Bre- 
ton, and  not  less  than  ten  of  the  United  States,  but 
never  saw  petroleum  in  a  coal-mine,  or  even  smelt  it ; 
and  this  is  an  article  that  never  waits  for  an  introduc- 
tion, but  salutes  the  olfactories  at  once.  Of  course,  if 
this  came  from  coal,  coal-mines  would  be  the  places  in 
which  to  discover  it ;  coal  neighborhoods  should  abound 
with  it,  coal-miners  be  familiar  with  it ;  and  it  should 
never  be  found  in  rocks  older  than  the  coal-measures. 
The  contrary  of  all  this  is  true.  Where  it  is  found  in 


118  LECTURES  ON  GEOLOGY. 

the  coal-measures,  it  has  been  forced  up  from  under- 
lying beds  in  which  it  was  originally  contained. 

In  this  country,  nearly  all  the  oil  hitherto  obtained 
has  been  from  beds  that  lie  below  the  coal-measures, 
and  sometimes  at  a  great  depth  below  them.  On  Oil 
Creek,  in  Pennsylvania,  it  is  found  by  boring  in  shales 
and  sandstones,  sometimes  to  a  depth  of  a  thousand 
feet ;  these  beds  belonging  to  the  Chemung  group  of  the 
Devonian  formation,  and  many  hundred  feet  below  the 
coal-measures.  At  Enniskillen,  in  Canada  West,  where 
the  oil  has  at  one  time  come  up  in  springs,  and  over- 
flowed, leaving  a  thick  bed  of  asphaltum  covering  the 
ground  for  an  acre,  the  limestone  in  which  borings  are 
made  contains  characteristic  fossils  of  the  Hamilton 
group  of  the  Devonian  formation.  The  oil-wells  in 
Western  Kentucky,  and  in  some  parts  of  Tennessee, 
are  in  the  Trenton  limestone,  —  that  is,  in  the  lower 
Silurian  formation ;  and  I  have  seen  oil  even  at  the 
base  of  this.  The  same  oil  floats  on  the  surface  of  a 
limestone  quarry  near  Chicago,  the  limestone  belonging 
to  the  Niagara  group  of  the  Silurian  formation  ;  showing 
conclusively  that  it  has  no  necessary  connection  with 
coal. 

But  may  it  not  have  been  produced  from  sea-plants, 
as  coal  has  been  from  land-plants,  as  several  eminent 
geologists  have  supposed?  The  quantity  of  free  oil. 
existing  in  the  earth  seems  to  forbid  this.  I  saw  a  well 
in  Western  Virginia  which  produced  twenty-eight  thou- 
sand barrels  in  ten  months.  From  three  wells  near  Oil 
Creek,  one  thousand  barrels  spouted  in  twenty-four 
hours ;  and  from  one,  three  thousand  seven  hundred  and 
forty.  The  "  Big  Phillips  "  Well  struck  oil  in  October, 
1861,  at.  a  depth  of  four  hundred  and  eighty  feet.  It 


LECTURES  ON  GEOLOGY.  119 

yielded  about  three  thousand  barrels  a  day.  The  oil 
rushed  out  with  such  violence,  that  the  well  could  not 
be  tubed  for  several  days ;  and  it  has  been  calculated 
that  forty  thousand  barrels  of  oil  were  lost  in  the  creek 
before  it  could  be  collected. 

The  "Noble"  Well  struck  oil  in  April,  1863.  Its 
daily  yield  was  about  fifteen  hundred  barrels,  at  which 
rate  it  flowed  for  six  months. 

There  must  be  lakes  of  petroleum  to  render  such 
flows  possible.  Where  are  the  bodies  of  fucoids  or  sea- 
weeds from  which  this  oil  could  flow  ?  The  sea-weeds 
of  the  Silurian  and  Devonian  times  (in  whose  beds  the 
greatest  quantity  of  petroleum  is  found)  were  so  loose 
in  structure,  and  contained  so  little  bituminous  matter, 
that  their  impressions  do  not  even  darken  the  light- 
colored  shales  in  which  they  are  found  embedded.  Had 
these  plants  been  as  oily  as  fish,  their  bodies  would  have 
left  dark  impressions  on  the  shales,  as  the  bodies  of 
fish  do;  and  if  they  were  not  as  oily  as  fish,  or  as  bitu- 
minous as  land-plants,  by  what  possibility  could  they 
produce  lakes  of  oil  ?  If  the  plants  had,  indeed,  been 
oily,  no  oil  could  have  been  collected  from  them,  unless 
preserved  from  contact  with  the  air  and  water.  Each 
plant  being  separated  from  its  companions,  on  being 
buried  in  mud,  the  oil,  supposing  any  to  exist,  would 
have  been  absorbed  by  it,  and  thus  lost. 

Has  the  oil  been  distilled  from  bituminous  shales,  as 
some  suppose  ?  I  think  not.  It  requires  a  strong  heat 
to  distil  oil  from  shales ;  and  generally,  where  petroleum 
is  found  in  the  greatest  abundance,  there  is  the  least 
appearance  of  igneous  action. 

How  was  it  produced,  then  ?  It  is  a  coral-oil,  and  not 
a  cooZ-oil.  I  have  in  my  possession  numerous  specimens 


120  LECTUEES  ON  GEOLOGY. 

of  fossil  coral,  obtained  from  Devonian  and  Silurian  rocks 
belonging  to  the  family  offavosites,  or  honeycomb-stone, 
as  the  name  means,  the  cells  of  which  very  much  resem- 
ble those  of  the  honeycomb  ;  and,  as  the  cells  of  the  honey- 
comb are  filled  with  honey,  these  cells  are  filled  with  oil. 
I  have  found  oil  in  some  specimens  nearly  as  limpid  as 
water;  and,  by  heating  the  coral,  oil  runs  out  readily. 
I  have  seen  these  oil-bearing  corals  at  Smokes  Creek, 
where  there  are  coral-reefs  full  of  it ;  in  the  Silurian  lime- 
stones of  Middle  Tennessee;  at  Williamsville,  near  Buf- 
falo ;  and  in  rocks  near  Penn  Yan,  in  New  York.  In  the 
State  Collection  of  Fossils  at  Albany,  and  in  the  Montreal 
Geological  Cabinet,  there  are  numerous  specimens.  Pro- 
fessor Dana  informs  us,  that  it  flows  in  drops  from  a 
fossil  coral  at  Montmorenci,  Can.,  and  at  Watertown,  N.Y. 
It  might  be  supposed  that  this  oil  filled  the  cavi- 
ties of  the  corals,  as  it  might  any  other  cavity  in  the 
rocks :  but  I  have  found  it  repeatedly  in  these  corals, 
and  in  no  other  part  of  the  rock,  invariably  accompany- 
ing the  corals,  and  never  connected  with  any  other  fossil ; 
these  corals  frequently  in  the  centre  of  solid  limestone 
blocks.  Reefs  of  such  coral  would  furnish  oil  in  quanti- 
ties sufficient  to  account  for  the  immense  deposits  that 
have  been  discovered.  Preserved  by  them  in  compact 
bodies,  the  oil  taking  up  at  least  half  the  space  of  the 
coral-reef,  we  can  readily  suppose,  that  when  the  cells 
were  crushed  by  the  superincumbent  weight  of  rock, 
or  during  upheavals  and  subsidences,  cavities  would  be 
filled  by  it,  and  porous  sandstones  receive  it  like  a  sponge. 
It  is,  then,  an  animal  production,  and  not  a  vegetable 
one.  It  is  a  product  of  the  ocean,  and  not  of  the  land  ; 
being  almost  invariably  associated  with  salt  water  from 
the  bottoms  of  seas  that  then  covered  a  large  portion  of 


LECTURES  ON  GEOLOGY.  121 

Western  New  York,  Pennsylvania,  Virgiua,  Eastern 
Ohio,  Kentucky,  and  Tennessee.  It  is  not  formed  from 
the  bodies  of  the  coral  polyps,  as  some  have  supposed, — 
for,  when  dry,  they  are  a  mere  film,  that  could  be  blown 
away  by  a  child's  breath,  —  but  secreted  by  them  princi- 
pally, though  not  exclusively,  during  the  Devonian  times, 
storing  away  fuel  for  the  coming  ages  as  the  plants  did 
during  the  carboniferous  period. 

"  The  old-rock  corals/7  says  Professor  Owen,  "  are  re- 
markable for  the  manner  in  which  they  are  partitioned 
off  by  horizontal  *  tabulae.'  Of  the  one  hundred  and 
twenty-nine  Silurian  corals,  one  hundred  and  twenty-one 
belong  to  the  tabulated  divisions."  These  tabulated 
corals,  that  thus  flourished  in  the  old  times,  seem  to 
have  been  the  oil-secreters.  And  as  these  tabulated 
corals  diminish  in  number  as  we  ascend  geologically,  so, 
I  venture  to  say,  it  will  be  found  that  the  younger 
formations  contain  less  oil;  or,  where  much  oil  is  found 
in  more  recent  rocks,  it  has  been  forced  up  from  older 
deposits  underlying  them. 

In  some  places,  petroleum  is  nearly  as  transparent  as 
water,  as  it  is  found  in  wells  on  the  Little  Beaver,  Ohio ; 
at  Titusville,  of  a  dark-green  color,  but  quite  liquid  ;  at 
Enniskillen,  C.  W.,  thick  as  tar :  and  on  the  ground  above, 
where  it  has  overflowed,  you  can  walk  upon  it  in  winter, 
but  find  it  sticky  in  summer;  as  also  in  Western 
Colorado,  where  the  Indians  told  me  they  had  thus  caught 
bears  stuck  fast  in  it.  On  the  shores  of  the  Dead  Sea 
it  is  as  hard  as  cannel-coal,  so  that  the  Arabs  inscribe 
sentences  upon  it ;  and  in  New  Brunswick  at  the  famous 
Albert  Mine,  in  Western  Virginia,  Colorado,  and  Utah,  we 
find  it  as  a  black,  solid,  hard,  shining  coal,  readily  break- 
ing into  fragments  ;  while,  in  the  lower  Silurian  of 


122  LECTURES   ON  GEOLOGY. 

Canada  East,  we  occasionally  find  anthracite  coal,  as  I 
have  seen  it  in  the  cells  of  corals,  which  is  the  same 
article  operated  upon  by  heat,  —  metamorphosed  petro- 
leum-coal. 

When  oil  is  thus  operated  upon  by  the  heat  of  the 
earth's  interior,  carburetted  hydrogen  gas  is  evolved, 
which  is  inflammable  :  wherever  this  is  found  issuing  in 
large  quantities  from  rocks  that  are  below  the  coal- 
measures,  it  indicates  the  presence  of  this  oil  in  the 
vicinity,  though  it  may  be  at  a  considerable  depth. 

The  amount  of  this  oil  is  much  greater  than  is  gener- 
ally supposed.  A  large  part  of  Canada  West,  Michigan, 
Kentucky,  Kansas,  as  well  as  Ohio,  Pennsylvania,  and 
Virginia,  are  underlaid  with  it.  Western  New  York 
contains  considerable,  as  the  gas-springs  in  so  many 
parts  of  it  bear  witness.  The  town  of  Fredonia,  N.Y., 
has  for  many  years  been  lighted  by  the  gas  issuing  from 
one  of  these  springs  ;  and  I  have  seen  a  store  near  Penn 
Yan  heated  by  the  gas,  the  supply  being  much  greater 
than  was  necessary  for  that  purpose. 

Fig.  11.  There  is  a  fine  exposure  of  the  rocks 

of  the  Hamilton  group  at  Eighteen-mile 
Creek,  on  Lake  Erie ;  and  ako  on  a  creek 
emptying  into  Seneca  Lake,  near  Bellona, 
in  New  York:  from  which  localities  count- 
less thousands  of  shells,  corals,  crinoids, 
and  trilobites,  have  been  carried  off,  while 
the  water  and  the  frost  are  constantly  ex- 
posing a  new  crop.  Fig.  11  represents  a  specimen  of 
Phacops  bufo  (lens-eyed  toad),  one  of  the  trilobites  of  this 
period.  Its  eyes  are  prominent,  and  contain  sixty-six 
lenses. 

The    Portage    group,  consisting   of  dark   shales  and 


LECTURES  ON  GEOLOGY.  123 

flagstones,  succeeds  the  Hamilton,  and  appears  to  have 
been  deposited  in  a  muddy  ocean  very  unfavorable  to 
life;  for  fossils  are  rarely  found  in  it.  In  some  parts  of 
Pennsylvania,  it  attains  a  thickness  of  seventeen  hundred 
feet,  but  thins  out  toward  the  Mississippi, 

The  Cheraung  group  contains  the  highest  beds  of  the 
Devonian  formation  in  America.  It  is  so  called  from 
the  Cheumng  River,  in  the  State  of  New  York,  -where  it 
is  well  exhibited.  It  consists  of  a  series  of  shales  and 
shaly  sandstones  of  an  olive  or  greenish  color ;  and,  in 
many  places,  abounds  with  fossils.  Large  slabs  may  be 
taken  out  completely  covered  with  casts  of  shells.  Im- 
pressions of  plants  are  occasionally  found  in  this  group, 
that  resemble  the  ferns  of  the  coal  period.  It  covers 
a  great  extent  of  surface  in  the  southern  counties  of 
New  York  and  in  North-western  Pennsylvania. 

In  rocks  at  Elgin,  in  Scotland,  supposed  to  be  of  the 
Devonian  age,  the  remains  of  a  small  reptile  about  six 
inches  in  length  have  been  discovered ;  and,  in  the  same 
quarry,  thirty-four  footsteps  of  a  reptile,  —  probably  am* 
phibian.  The  tracks  are  about  an  inch  broad;  the 
length  of  the  stride,  four' inches. 

What  strange  stories  this  stony  record  reveals  !  For 
millions  of  years,  this  ponderous  globe  rolled  round ^  and 
round ;  rains  fell,  winds  blew,  tides  ebbed  and  flowed ; 
by  day  the  sun,  and  by  night  the  queenly  moon  and 
all  the  stars,  looked  down,  the  guardians  of  the  growing 
world  :  yet,  during  all  this  immense  period,  we  find  noth- 
ing higher  for  which  all  this  was  done,  nothing  to  behold 
all  the  pomp  and  glory,  but  a  reptile  six  inches  long ! 
The  tree  was  growing  whose  fruit  should  be  humanity ; 
and  the  ages  were  necessary  to  knit  its  giant  trunk  and 
perfect  its  branches. 


124  LECTURES    ON  GEOLOGY. 

No  remains  of  reptiles  hS,ve  yet  been  discovered  in 
American  Devonian  rocks :  they  may,  however,  yet  be 
found.  I  have  no  doubt  that  numerous  reptiles  lived  on 
this  continent,  even  before  the  close  of  the  Devonian 
period ;  for  the  first  discovery  of  an  animal  in  a  fossil 
condition  is  very  unlikely  indeed  to  coincide  with  its 
first  appearance  upon  the  globe.  We  may  as  well  expect 
to  find  the  remains  of  the  first  man  in  a  fossil  condition 
as  to  find  the  first  Torms  of  any  type. 

During  the  Devonian  period,  it  is  evident  that  the 
land-surface  of  the  globe  was  still  of  limited  extent, 
though  constantly  enlarging.  At  its  commencement,  the 
northern  portion  of  New  York  was  above  the  waves;  but, 
at  its  close,  nearly  the  whole  of  the  State  was  high  and 
dry,  and  forms  of  vegetation  covered  at  least  a  portion 
of  it.  This  land  was  probably  connected  with  a  small 
continent  lying  to  the  north  and  east  now  covered  by  a 
portion  of  the  Atlantic  Ocean.  The  climate  was  still 
warm,  even  to  the  poles ;  and  the  ocean  everywhere  the 
abode  of  forms  analogous  to  those  now  found  only  in 
tropical  regions.  Devonian  fossils  have  been  brought 
from  the  shore  of  the  Arctic  Ocean,  that  cannot  be  dis- 
tinguished from  similar  fossils  in  New  York. 

As*  early  as  the  Hamilton  period,  we  know  that  respec- 
table trees  existed.  I  have  seen  impressions  of  their 
trunks  in  shales  at  the  Falls  of  the  Ohio,  and  of  long, 
lance-shaped  leaves  that  must  have  been  of  great  thick- 
ness. It  is  highly  probable  that  flags  and  reeds  abound* 
ed  by  the  water-courses  and  in  the  swamps  ;  while  low 
forests  of  tree-ferns  existed  where  the  soil  was  suffi- 
ciently thick  for  their  growth,,  foreshadowing  the  age 
of  plants  which  follows. 

Where  land  vegetation  abounds,  we  naturally  look  for 


LECTURES  ON  GEOLOGY.  125 

insects,  which  are  invariably  found  accompanying  it  at 
the  present  time.  Recently,  the  remains  of  flies,  some 
of  which  were  quite  large,  have  been  discovered  in 
Devonian  slates  near  St.  John,  N.B.  From  their  size, 
we  may  be  sure  that  these  were  not  the  first  representa- 
tives of  the  insect  world. 


LECTURE   DDL 


CARBONIFEROUS  PERIOD. 

AGE    OF    PLANTS. 

WE  have  already  traced  our  planet  over  a  considerable 
portion  of  the  pathway  of  its  progress :  at  first,  proba- 
bly, a  nebulous  mass,  —  a  globe  of  fire-mist,  looking  like 
a  comet,  whose  flaming  orb  startles  the  drowsy  world,  as 
it  flies  round  arid  round,  bathing  its  burning  sides  in  the 
frigid  space  which  surrounds  it ;  then  a  fluid  world,  the 
red  waves  rolling  over  its  agitated  surface  continually, 
while  the  sulphurous  clouds  hang  sullenly  above  it; 
then  a  bare,  black,  rugged  world,  whose  heated  floor  is 
rougher  and  flintier  than  the  slag  of  an  iron  furnace. 
After  interminable  ages,  it  cools,  the  vapors  condense, 
the  valleys  are  filled,  and  oceans  are  born,  amid  thunder- 
ings,  bellowings,  and  battles  most  dire,  —  fire  and  water 
for  ages  in  deadly  combat.  Now  peace  and  the  spirit 
of  life  brood  over  the  world.  In  the  shallow  oceans, 
blood  warm,  the  radiata  spread  their  tentacles,  the  coral 
polyps  build  their  stony  habitations  j  while  the  leathery- 
leafed  algee  take  root  upon  the  rocky  reef.  The  mollusks 
anchor  themselves  to  the  rocks,  creep  with  their  broad 
feet  over  the  muddy  sea-bottom,  or  range  from  the 

126 


LECTURES  ON  GEOLOGY.  127 

twilight  depths  to  the  surface,  where  they  propel  their 
long  floats  over  the  waves.  The  articulata  skull  their 
boats  in  the  sheltered  bays  ;  while  beneath  them  zo- 
ophytes of  varied  hues  bloom  in  beauty  like  a  garden  of 
flowers.  Now  moss-like  plants  carpet  the  rough  rocks 
upon  the  land,  and  ferns  fringe  them  ;  reeds  spring  up 
by  the  rivers,  and  tree-ferns  wave  their  heads  in  triumph 
on  the  higher  grounds ;  reptiles  crawl  and  hop  on  the 
muddy  margin  of  the  sea,  the  lordliest  guests  the  world 
has  yet  entertained.  It  is  still  marching  on  to  its  goal ; 
and  its  next  step  comes  up  for  our  consideration. 

Above  the  Devonian  formation  lies  the  carboniferous, 
so  called  on  account  of  the  carbon  locked  up  in  its  coal- 
beds,  to  us  the  most  important  members  of  the  formation. 
Underlying  these  coal-beds  are  generally  found  beds 
that  were  deposited  at  the  bottom  of  the  sea,  —  thick  beds 
of  conglomerate  or  pudding-stone,  sandstones,  or  beds  of 
limestone.  In  South-western  Indiana,  in  Illinois,  Ken- 
tucky, Iowa,  and  Missouri,  is  a  solid  limestone,  in  some 
places  a  thousand  feet  thick:  it  is  known  by  the  name 
of  the  sub-carboniferous  limestone,  from  the  fact  of  its 
underlying  the  coal-measures,  which  it  invariably  does,  — 
a  fact  worthy  of  note  to  those  in  search  of  coal  in  its 
neighborhood.  In  England,  this  limestone  is  known  by 
the  name  of  mountain  limestone,  from  the  fact  of  its 
occurrence  in  Derbyshire,  the  most  mountainous  country 
in  England,  where  it  attains  a  thickness  of  twelve 
hundred  feet.  It  has  been  termed  encrinal  limestone, 
three-fourths  of  it,  in  many  places,  being  composed  of 
crinoids,  or,  as  they  are  sometimes  called,  encrinites. 
Whore  the  rock  has  worn  away  by  the  action  of  the 
atmosphere,  the  round  joints  of  the  crinoids,  being 
harder  than  the  surrounding  rock,  are  frequently  found 


128  LECTURES  ON  GEOLOGY. 

lying  loose  in  the  soil,  and  £re  gathered  by  the  children 
in  England, 'and  strung  for  beads.  They  are  called  there 
wheel-whirls,  pulley-stones,  and  St.  Cuthbert's  beads  ;  for 
there  is  an  old  legend  which  attributes  their  formation 
to  this  saint.  Thus  Walter  Scott  says,  — 

"  But  fain  St.  Hilda's  nuns  would  learn 
If  on  a  rock  by  Lindisferne 
St.  Cutkbert  sits,  and  toils  to  frame 
The  sea-born  beads  that  bear  his  name : 
Such  tales  had  Whitby's  fishers  told, 
And  said  they  might  his  shape  behold, 

And  hear  his  anvil  sound,  — 
A  deadened  clang,  a  huge,  dim  form, 
Seen  but  and  heard  Avhcn  gathering  storm 
And  night  were  closing  round." 

Imagine  you  obtain  a  glimpse  of  the  saint  on  the 
weather-beaten  rock,  as  the  storm  gathers  around  him 
beating  away  on  his  anvil,  and- forging  his  famous  beads. 
But,  as  Hugh  Miller  justly  observes,  if  lie  made  all  these 
beads,  he  must  have  been  the  busiest  saint  in  the 
calendar ;  for  they  are  scattered  over  the  world  by  count- 
Fig.  12.  less  millions.  These  fossils  bear  in  Ger- 
many the  name  of  Spangen-steim,  or  bead- 
stones  ;  lioeder  -  steine,  or  wheel -stones; 
while  in  Westphalia  they  are  called  Hii- 
nen-thranen,  "  giant's-tears."  I  have  seen 
places  in  Southern  Indiana  where  the  body 
of  a  wagon  might  be  filled  with  these 


fossils  in  a   short  time,  so  numerous   are 


Actinocrinus  probosci- 


Fig.  12  represents  the  cup,  or  body,  of  one  of  the 
crinoids  from  the  crinoidal  limestone  of  Burlington,  in 
Iowa.  It  is  called  an  actinocrinus  or  rayed  crinoicl,  from 


LECTURES  ON  GEOLOGY.  129 

the  ray-like  side-arms  which  project  from  it.     This  genus 
is  v^ry  abundant  in  South-western  Indiana. 

In  Illinois,  the  following  groups  of  rocks,  in  descending 
order,  have  been  made  out  between  the  base  of  the 
coal-measures  and  the  Devonian  formation:  — 

CHESTER  GROUP,  500  to  800  feet. 

ST.  Louis  GROUP,  50  to  200      „ 

KEOKUK  GROUP,  100  to  150      „ 

BURLINGTON  LIMESTONE,  25  to  200      „ 
KINDERHOOK' GROUP,      100  to  150      „ 

These  are  all  limestones,  and  each  group  contains  char- 
acteristic fossils  by  which  it  can  be  identified.       Fig.  13. 
They  abound   in  fossil  shells,  and  in  some 
places  with  fish  teeth  and  bones.     In  Illinois, 
as  also  in  various  parts  of  Iowa  and  Missouri, 
is  found  a  fossil  bryozoan,  called,  from  its 
resemblance    to    the    Archimedean    screw, 
Archimedes  (Fig.  13) ;  and  hence  the  lime- 
stone in  which  it  is  found  is  called  Archime- 
des limestone.  ArtWSSi:Woip- 

The  sub-carboniferous  limestone  has  been  termed  metal- 
liferous limestone,  from  the  abundance  of  lead  that  has 
been  found  in  it  in  various  places.  The  lead-mines  of 
Derbyshire  and  Durham  in  England,  and  of  the  Hartz 
Mountains  in  Germany,  are  in  this  limestone.  In  Derby- 
shire and  Durham,  this  lead  is  found  in  the  vicinity  of 
trap-dikes  and  volcanic  deposits ;  and  the  heat  and 
eruptions  connected  with  them  may  have  driven  the 
lead  into  rocks  as  high,  geologically,  as  these. 

Another  name  has  been  given  to  this  limestone,  and 
perhaps  the  most  appropriate  of  all,  —  that  of  cavernal 
limestone.  The  great  caves  of  the  world  are  in  it,  —  those 


130  LECTURES  ON  GEOLOGY. 

of  Derbyshire  in  England,  o£ Indiana,  of  Missouri,  and  of 
Kentucky.  The  Wyandotte  Cave,  which  has  been  traced 
through  its  various  windings  for  twenty-seven  miles,  is 
in  this  limestone  ;  and  the  Mammoth  Cave,  world-famous. 

In  visiting  Wyandotte  Cave,  in  Southern  Indiana,  you 
climb  a  hill,  near  the  top  of  which  the  opening  to  t:ie 
cave  is  situated.  After  sliding  down  a  narrow  passage, 
you  arrive  at  Bat's  Lodge,  where  bats  by  thousands, 
hanging  down  from  the  roof,  show  the  propriety  of  its 
name.  After  numerous  passages  arid  halls  have  been 
passed  through,  you  enter  the  Grand  Hall,  said  to  be  two 
acres  in  extent,  with  a  hill  near  the  centre  of  it  two 
hundred  feet  high,  composed  of  blocks  large  and  rude, 
which  have  fallen  from  the  roof  at  various  times.  On 
the  top  of  it  is  a  white  pillar  of  stalagmite,  formed  by 
continual  dropping  of  limewater  upon  it:  each  drop 
has  left  a  thin  film  of  lime,  until  this  monument  has  been 
reared.  In  some  chambers,  stalactites,  like  stony  icicles, 
hang  from  the  roof;  while,  in  others,  stalactites  growing 
downward,  and  stalagmites  beneath  them,  growing  up- 
ward by  the  constant  dropping,  have  united,  forming 
alabaster  pillars,  that  seem  to  support  the  roof  above 
them.  Fantastic  forms  similarly  produced  are  seen  on 
every  side,  —  tables,  thrones,  pulpits  ;  while  radiant  crys- 
tals shine  resplendently,  as  you  walk,  torch  in  hand, 
through  the  echoing  aisles. 

The  Mammoth  Cave  is  by  far  the  largest  discovered 
cave,  and  the  most  remarkable.  Its  long,  broad  passages, 
and  immense  halls,  carved  out  of  solid  rock,  in  the  moun- 
tain's heart,  by  flowing  water  ;  its  deep  cavities  dug  by 
falling  cataracts;  its  wide,  deep  river;  the  Workman 
that  accomplished  it  all  in  the  darkness,  where  swim  the 
almost  transparent  blind-fish,  —  once  seen,  are  daguerro- 


LECTURES   ON  GEOLOGY.  ii* 

typed  on  the  soul  forever.  If  you  wish  to  have  a  sensa- 
tion of  the  awful  and  unearthly,  nowhere  can  you  gratify 
that  wish  so  completely  as  on  Echo  Kiver,  in  the  Mam- 
moth Cave.  Who  but  the  poet  can  do  justice  to  such 
scenes  as  these  ?  Prentice,  after  a  visit  to  Mammoth 
Cave,  says, — 

"  All  day,  as  day  is  reckoned  on  the  earth, 
I've  wandered  in  these  dim  and  awful  aisles 
Amid  the  beautiful,  the  wild,  the  gloomy,  the  terrific : 
Crystal  founts,  almost  invisible  in  their  serene 
And  pure  transparency ;  high  pillared  domes, 
With  stars  and  flowers  all  fretted  like  the  halls 
Of  Oriental  monarchs ;  rivers  dark 
And  drear,  and  voiceless  as  Oblivion's  stream, 
That  flows  through  Death's  dim  vale  of  silence ;  gulfs 
All  fathomless,  down  which  the  loosened  rock 
Plunges,  until  its  far-off  echoes  come 
Fainter  and  fainter,  like  the  dying  roll 
Of  thunders  in  the  distance ;  Stygian  pools, 
Whose  agitated  waves  give  back  a  sound 
Hollow  and  dismal,  like  the  sullen  roar 
In  the  volcano's  depths." 

Over  a  large  part  of  Indiana  and  Kentucky,  there  are 
numerous  sink-holes,  or  swallow-holes  as  they  are  some- 
times termed,  —  round  hollows  produced  by  water  sink- 
ing into  caves,  and  sweeping  the  earth  down  with  it. 
So  numerous  are  they  in  some  places,  that  it  is  impos- 
sible to  plough  the  land.  A  large  part  of  that  country  is 
underlaid  by  immense  caves,  adorned  as  never  was  king's 
abode,  waiting  for  the  eye  of  intelligence  to  behold. 

While  conditions  were  favorable  for  the  deposition 
of  limestone  in  some  places,  they  seem  to  have  been 
equally  favorable  for  the  formation  of  sandstones  and 
conglomerates  in  others.  At  Pottsville  and  its  neigh- 


132 


LECTURES   ON   GEOLOGY. 


borhood,  underlying  the  £reat  anthracite  beds,  are 
shales  and  sandstones  of  this  age,  from  two  to  three 
thousand  feet  in  thickness.  In  Nova  Scotia  are  red 
sandstones,  and  red  and  green  marls,  estimated  at  six 
thousand  feet  in  thickness.  In  some  parts  of  Pennsylva- 
nia, Ohio,  Indiana,  Kentucky,  and  Tennessee,  a  conglom- 
erate, made  of  coarse  sand  and  white  quartz  pebbles 
firmly  cemented  together,  underlies  the  coal-measures, 
and  forms  an  excellent  guide  in  searching  for  coal.  In 
Northern  Ohio  and  Western  New  York,  this  conglom- 
erate is  underlaid  by  blue  shale.  This  having  been 
washed  out  in  places,  immense  blocks  of  the  conglom- 
erate have  been  detached,  and  lie  exposed  on  high 
points,  where  they  are  styled  rock-cities.  They  may 
be  seen  south  of  Olean,  in  New  York,  near  the  Pennsyl- 
vania line.  Nelson  Ledges,  on  the  Western  Reserve,  and 
Little  Mountain,  near  Painesville,  in  Ohio,  are  other  ex- 
posures of  this  remarkable  rock,  which  show  how  massive 
strata  have  been  broken  up  by  the  action  of  the  elements. 
Below  the  coal-measures,  near  Pottsville,  Penn.,  Isaa~ 

Fig.  14. 


Siiuropua  pnmaeviis. 

Lea   discovered   the    footprints  of  a  reptile,  which  be 
called  Sauropus  primcevus,  "  first  lizard  foot."     Fig.  14 


LECTURES  ON  GEOLOGY.  133 

represents  the  slab- on  which  they  were  found,  and  is 
one-eighth  the  natural  size.  "  The  animal  appears  to 
have  had  five  toes  on  its  fore-feet,  and  four  toes  on  the 
hind-pair;  longer  legs  than  the  crocodile,  there  being 
no  trace  of  the  dragging  of  the  feet ;  and  a  slender  tail, 
which  left  a  groove-like  impression.  The  stride  from 
toe  to  toe  measures  thirteen  inches ;  and  the  feet  are 
about  three  and  a  half  inches  long.  The  hind-feet 
stepped  upon  nearly  the  same  spot  as  the  fore -feet, 
causing  some  obliteration  of  the  first  impression." 

In  1851,  Professor  H.  D.  Rogers  discovered,  in  the  same 
red  shales,  footprints  of  three  species  of  four-footed 
animals,  all  of  which  were  five-toed :  the  largest  had  a 
length  of  stride  of  about  nine  inches.  Upon  the  same 
slabs  that  contained  these  footprints  were  shrinkage- 
cracks,  such  as  are  made  by  the  sun's  heat  upon  mud ; 
and  prints  of  rain-drops,  with  signs  of  water  trickling 
on  a  wet  beach ;  showing  conclusively  that  the  animals 
which  made  the  prints  were  out  of  the  water,  and  must, 
therefore,  have  been  air-breathers. 

Above  this  come  the  coal-measures.  These  are  com- 
posed of  beds  of  sandstone,  shale,  coal,  and  occasionally 
thin  limestones,  alternating  with  each  other.  The  beds 
passed  through  in  sinking  for  coal  in  the  Kanawha  Val- 
ley, in  Western  Virginia,  give  a  good  idea  of  the  way  in 
which  they  lie.  They  commenced  to  dig  on  a  bed  of 
coarse-grained  sandstone  containing  fossil  trees,  which 
they  found  to  be  eighty  feet  thick ;  below  that  was  a 
bed  of  iron-ore,  a  foot  thick ;  then  hard,  flinty  slate,  six 
feet  thick;  below  that  was  a  bed  of  bituminous  coal, 
four  feet  thick,  with  a  thin  bed  of  shale  beneath  it  con- 
taining impressions  of  plants  ;  then  coarse  sandstone, 
one  hundred  and  fifty  feet  thick :  when  they  came  upon 


134  LECTURES  ON  GEOLOGY. 

a  second  bed  of  coal,  four  fetet  thick ;  below  that,  sand- 
stone abounding  with  vegetable  impressions,  two  hun- 
dred feet  thick  ;  then  a  third  bed  of  coal,  twenty  inches 
thick,  with  a  bed  of  black  shale  beneath  it,  forty  feet 
thick,  containing  fossil  palms ;  beneath  that  was  a  bed 
of  coal,  six  feet  thick,  the  principal  seam  of  coal  in  the 
Kanawha  Valley  j  below  that  is  sandstone,  over  which 
the  Kanawha  River  runs. 

The  number  of  beds  alternating  with  each  other  in 
this  way  is  sometimes  very  great:  the  coal  generally 
bears  but  a  small  proportion  to  the  accompanying  beds. 
Thus  at  South  Joggins,  in  Nova  Scotia,  where  the  true 
coal-measures  are  seven  thousand  feet  in  thickness, 
there  are  hundreds  of  beds  of  sandstones,  shales,  under- 
clays,  and  limestones,  with  seventy-six  beds  of  coal ;  but 
there  are  only  forty-five  feet  of  coal  in  the  whole,  and 
very  few  of  the  beds  are  thick  enough  to  pay  for 
working. 

What  could  have  produced  this  singular-looking, 
black,  inflammable  rock  ?  How  many  times  this  was 
asked  before  Science  could  return  an  answer !  This  she 
now  does  with  confidence.  Coal  was  once  growing, 
vegetable  matter.  Take  up  a  piece  of  bituminous  coal, 
and,  on  closely  examining  it,  you  will  find  in  most  cases 
what  look  like  fragments  of  charcoal  j  the  fibres  of  the 
original  wood  plainly  visible  in  them.  By  grinding 
down  a  piece  of  bituminous  coal  very  thin,  and  examin- 
ing it  through  a  microscope,  the  very  vessels  of  the 
wood  may  be  distinctly  perceived.  Nor  is  this  all: 
examine  the  mine  where  the  coal  is  obtained,  and  on 
the  surface  of  the  shale,  immediately  above  the  coal, 
you  will  find  innumerable  impressions  of  leaves  and 
branches  as  perfect  as  artist  ever  drew.  Dr.  Buck- 


LECTURES  ON  GEOLOGY.  135 

land  thus  eloquently  describes  the  Bohemian  coal-mines : 
"  The  most  elaborate  imitations  of  living  foliage  upon 
the  painted  ceilings  of  Italian  palaces  bear  no  compari- 
son with  the  beauteous  profusion  with  which  the  gal- 
leries of  these  instructive  coal-mines  are  overhung. 
The  roof  is  covered  as  with  a  canopy  of  gorgeous  tapes- 
try, enriched  with  festoons  of  most  graceful  foliage, 
flung  in  wild,  irregular  profusion  over  every  portion  of 
its  surface.  The  effect  is  heightened  by  the  contrast 
of  the  coal-black  color  of  these  vegetables  with  the 
light  ground-work  of  the  rock  to  which  they  are 
attached.  The  spectator  feels  himself  transported,  as 
if  by  enchantment,  into  the  forests  of  another  world;  he 
beholds  trees  of  forms  and  characters  now  unknown 
upon  the  surface  of  the  earth,  presented  to  his  senses 
almost  in  the  beauty  and  vigor  of  their  primeval  life." 

Still  further  evidence  of  the  vegetable  character  of 
coal  is  presented  in  the  shale,  or  underclay,  that  lies 
immediately  beneath  it.  In  that,  we  find  the  very  roots 
of  the  original  plants  still  ramifying  through  the  shale, 
once  the  soil  in  which  they  grew.  Of  the  seventy-six 
beds  of  coal  found  at  South  Joggins,  N.S.,  all  but  two 
of  them  have  their  accompanying  under-clays,  with 
roots  of  plants  in  them.  This  is  also  the  case  in  Great 
Britain.  In  the  Welsh  coal-basin,  every  seam  of  coal  is 
underlaid  by  a  bed  of  what  the  miners  call  under-clay, 
or  fire-clay,  in  which  is  found  an  abundance  of  stig- 
maria-roots  ramified  through  it,  —  a  fact  first  publicly 
announced  by  Bakewell,  a  celebrated  English  geologist. 
With  the  impressions  of  plants  on  the  shale  above,  and 
the  roots  in  the  shale  below,  so  universally  accompany- 
ing the  coal,  who  can  doubt  the  vegetable  character  of 
Uie  beds  between  them  ? 


136  LECTURES  ON  GEOLOGY. 

But  how  could  vegetable  matter  ever  be  accumulated 
in  such  immense  masses  as  to  make  beds  of  coal,  such 
as  that  anthracite  bed  at  Wilkesbarre,  Penn./ thirty  feet 
thick?  It  would  require  ten  or  twelve  feet  of  green 
vegetable  matter  to  make  one  foot  of  solid  anthracite. 
Let  us  transport  ourselves  to  the  carboniferous  times, 
and  see  the  condition  of  the  earth,  and  this  may  assist 
us  to  answer  the  question.  Stand  on  this  rocky  emi- 
nence, and  behold  that  sea  of  verdure,  whose  gigantic 
waves,  as  the  wind  sweeps  over  it,  roll  in  the  greenest 
of  billows  to  the  horizon's  verge.  That  is  a  carbonif- 
erous forest.  In  the  distance,  mark  that  steamy  cloud 
floating  above  it ;  an  indication  of  the  great  evaporation 
constantly  proceeding  from  it.  The  scent  of  the  morn- 
ing air  is  like  that  of  a  green-house :  and  well  it  may 
be  ;  for  the  land  of  the  globe  is  a  mighty  hot-house ; 
the  crust  of  the  earth  is  still  thin;  its  internal  heat 
makes  a  tropical  climate  everywhere,  unchecked  by 
winter's  cold ;  and  it  forces  plants  to  a  most  luxuriant 
growth. 

Descend,  and  let  us  wander  through  this  forest,  and 
examine  it  more  minutely.  What  strange  trees!  —  no 
oaks,  hickories,  or  elms,  no  ash,  no  chestnut,  no  tree  that 
we  ever  saw  before.  It  looks  as  if  the  plants  of  a  boggy 
meadow  had  shot  up  in  a  single  night  to  a  height  of 
sixty  or  seventy  feet,  and  we  were  walking  about  among 
the  stalks.  We  are  in  a  gigantic  meadow  of  ferns,  reeds, 
club-mosses,  and  horse-tails.  A  million  columns  rise, 
whose  tufted  tops  make  twilight  at  mid-day.  So  close 
are  their  trunks  together,  that  we  can  scarcely  edge  our 
way  between  them.  The  ground  is  carpeted  with  trail- 
ing plants  completely  interwoven ;  and  we  can  lift  up 
long  masses  of  them,  revealing  the  dark-brown  floor  on 


LECTURES  ON  GEOLOGY.  137 

which  they  rest.  What  strange  trees  they  are  !  Here 
are  some  covered  with  scars  that  look  like  scales,  and 
give  the  trees  the  appearance  of  gigantic  serpents :  the 
scars  are  the  impressions  left  when  the  leaves  dropped 
off.  Near  the  tops  you  can  see  the  leaves  standing  out 
on  every  side  from  the  trunks,  which  are  entirely  desti- 
tute of  branches.  Other  trees  look  like  Corinthian  col- 
umns :  they  are  about  fifty  feet  high,  and  have  seal-like 
impressions  in  the  centre  of  the  flutings,  also  made  by 
the  leaves  that  once  stood  out  from  them  all  round  the 
tree,  as  the  spokes  of  a  cart-wheel  ray  from  the  hub. 
But  have  you  noticed  how  soft  and  spongy  the  ground 
is  ?  Shake,  and  the  trees  nod  for  an  acre  all  around. 
Beneath  us  lies  an  accumulation  of  vegetable  matter 
more  than  two  hundred  feet  in  thickness,  —  the  result  of 
the  growth  and  fall  of  plants  in  this  swamp  for  centuries. 
All  things  are  favorable  for  the  growth  of  vegetation. 
The  great  heat  of  the  ground  causes  water  to  rise 
rapidly  in  vapor ;  and  this  descends  in  showers,  supply- 
ing these  plants  with  continual  moisture.  The  air  con- 
tains a  large  proportion  of  carbonic-acid  gas,  poison  to 
animals,  but  food  to  plants,  which  out  of  it  build  up 
their  woody  structure.  Winds  at  times  level  these  trees 
as  with  a  stroke,  for  their  hold  on  the  earth  is  feeble ; 
and  these  twining  plants  weave  a  shroud  over  them,  and 
thus  the  mass  increases. 

We  are  now  on  the  edge  of  a  lake  abounding  with 
fish :  their  bony  scales  glitter  in  the  water  as  they 
pursue  their  prey.  It  is  raining.  While  in  the  woods, 
we  were  so  completely  sheltered,  that  the  drops  could 
not  reach  us.  Along  the  shore  are  shells  that  the  waves 
have  cast  up,  and  tracks  of  some  large  animal.  How  like 
the  impression  of  a  man's  hand  some  of  them  are  !  The 


138  LECTURES  ON  GEOLOGY. 

hind-feet  are  evidently  mudi  longer  than  the  fore-feet. 
There  is  the  frog-like  animal  that  made  them  ;  but  what 
a  size  !  It  must  be  six  feet  long.  Its  head  looks  like  that 
of  a  crocodile ;  for  its  jaws  are  furnished  with  long, 
strong,  sharp,  conical  teeth,  in  formidable  rows.  The 
shower  is  over  now ;  and,  though  the  sun  does  not  shine 
with  brilliancy,  we  can  see  his  place  in  the  heavens. 
Here  is  the  body  of  a  small,  dead  reptile.  Flies  are 
swarming  around  it,  and  beetles  feeding  upon  it ;  while 
dragon-flies  in  immense  numbers  are  flitting  around 
the  lake. 

The  continued  growth  and  deposition  of  this  vegeta- 
tioii  during  ages  must  have  produced  beds  somewhat 
analogous  to  the  peat-deposits  of  New  England  and 
Great  Britain.  In  the  Dismal  Swamp  of  Virginia,  there 
is  said  to  be  a  mass  of  vegetable  matter  forty  feet  in 
thickness.  There  is  a  peat-bog  on  the  banks  of  the 
Shannon,  in  Ireland,  three  miles  broad  and  fifty  long. 
When  conditions  were  -so  much  more  favorable,  beds 
four  hundred  feet  in  thickness  may  have  been  produced. 

This  accumulated  mass  of  vegetable  matter  must  be 
buried,  however,  before  we  can  have  a  coal-bed.  How 
was  this  accomplished  ?  •  The  very  weight  of  it  may 
have  caused  the  crust  of  the  earth  to  sink,  forming  a 
basin,  into  which  rivers,  sweeping  from  the  surrounding 
higher  country,  carry  down  mud  in  their  waters  which 
is  deposited  upon  it;  its  weight  pressing  upon  the 
vegetable  matter,  and  squeezing  it  into  half  its  original 
compass.  Sand  carried  down  in  a  similar  manner  sub- 
sequently, and  deposited  upon  the  mud,  the  mud  is 
pressed  into  shale  j  and  the  vegetable  matter,  still  more 
reduced  in  volume  by  this  extra  pressure,  is  better  pre- 
pared for  its  final  conversion  into  coal.  In  time,  the 


LECTURES  ON  GEOLOGY.  139 

basin  becomes  shallow,  from  the  deposition  of  sediment 
on  its  bottom,  and  the  wearing-down  of  its  outlet ;  and 
we  have  another  marsh,  with  its  myriad  plants ;  another 
accumulation  of  vegetable  matter,  by  a  similar  process, 
buried  in  like  manner.  Where  thirty  or  forty  seams  of 
coals  have  been  found  one  below  another,  we  have  evi- 
dence of  land  and  water  changing  places  as  many  times. 

When  vegetable  matter  is  excluded  from  the  air,  and 
under  great  pressure,  it  Decomposes  slowly,  parting  with 
carbonic-acid  gas ;  and  is  first  changed  into  lignite  or 
brown  coal,  and  then  into  bituminous  coal,  or  the  soft 
coal  that  burns  with  smoke  and  flame.  I  have  been  in 
a  coal-mine  where  the  carbonic-acid  gas  pouring  from  a 
crevice  in  the  coal  put  out  a  candle  placed  under  it  as 
readily  as  a  stream  of  water.  The  high  temperature  to 
which  the  coal  has  been  subjected  when  buried  at  great 
depths  has  probably  assisted  in  producing  the  change  ; 
and  where  that  temperature  has  been  very  high,  the 
coal  by  the  influence  of  the  heat  having  parted  with  its 
inflammable  gases,  we  have  the  hard  or  anthracite  coal, 
which  burns  with  little  or  no  flame,  and  without  smoke. 
It  is  indeed  coal  made  into  coke  under  tremendous  press- 
ure. 

The  conversion  of  vegetable  matter  into  coal  seems  to 
be  going  on  even  now.  In  Limerick,  in  the  State  of 
Maine,  there  are  peat-bogs  of  considerable  extent,  in 
which  a  substance  exactly  resembling  cannel-coal  has 
been  found.  In  some  of  the  Irish  peat-beds,  also,  a  simi- 
lar substance  has  been  discovered,  having  a  conchoidal 
fracture,  and  hard  enough  to  be  worked  into  snuff-boxes. 

It  was  at  first  supposed  that  the  plants  of  the  car- 
boniferous times  were  bamboos,  palms,  and  gigantic  cac- 
tuses, such  as  are  now  found  in  tropical  regions  ;  but  a 


140  LECTURES  ON  GEOLOGY. 

more  careful  examination  oT  them  shows,  that  with  the 
exception  of  the  tree-fern,  now  found  in  the  tropics, 
they  differ  from  all  existing  trees. 

A  large  proportion  of  the  plants  of  the  coal-measures 
were  ferns ;  some  authorities  say  one-half.  From  their 
great  abundance,  we  would  naturally  infer  the  great 
heat  and  moisture  of  the  atmosphere  at  the  time  when 
they  grew  ;  as  ferns  at  the  present  time  are  found  in 
the  greatest  abundance  on  small  tropical  islands,  where 
the  temperature  is  high,  and  the  air  is  charged  with 
moisture.  Ferns  are  the  most  abundant  plants  in  the 
islands  of  the  Indian  Archipelago. 

Fossil  remains  of  ferns  decrease  in  number  continually 
as  we  advance  from  the  carboniferous  period  to  the  pres- 
ent ;  and  in  this  fact  we  have  evidence  of  a  gradual  de- 
crease of  temperature,  resulting,  doubtless,  from  the  slow 
cooling  of  the  globe.  So  high,  indeed,  was  the  tempera- 
ture during  the  coal  period,  that  the  frigid  zones  were 
then  torrid ;  for  abundance  of  fossil  plants  similar  to 
those  of  our  ordinary  coal-measures  have  been  found  at 
Melville  Island,  in  latitude  75a,  and  at  Spitzbergen, 
within  the  arctic  circle. 

Next  to  the  ferns,  the  sigillaria,  of  which  about  fifty 
species  are  known,  were  perhaps  the  most  numerous 
plants,  and  largely  contributed  to  the  formation  of  coal. 

The  sigillaria,  with  their  tall,  fluted  columns,  attained, 
when  perfect,  a  diameter  of  three  feet,  and  a  height  of 
at  least  fifty  or  sixty  feet.  These  trees  have  been  found 
erect,  or  laid  horizontally  in  various  coal-mines  of  Europe 
and  America. 

In  1860,  four  hundred  and  ninety  species  of  plants  had 
been  iiscovered  in  the  European  coal-measures,  one  hun- 
dred and  forty-six  of  which  had  been  found  in  America  j 


LECTURES   ON  GEOLOGY. 


141 


the  whole  number  of  American  species  being  three  hun- 
dred and  fifty.  There  was  a  greater  resemblance  be- 
tween the  vegetation  of  the  two  continents  at  that  time; 
for  the  species  common  to  both  on  the  discovery  of 
America  were  few.  This  resemblance  during  the  coal 
period  was  probably  owing  to  the  similarity  of  climate 
and  surface  on  the  two  continents,  which,  we  have  good 
reason  to  believe,  was  much  greater  then  than  now. 

The  coal  formation  having  been  more  fully  explored 
than  any  other,  we  have  become  well  acquainted  with 
its  numerous  life-forms.  For  the  first  time  in  the  world's 
history,  we  have  positive  proof  that  life  existed  in  bodies 
of  fre.sh  water ;  some  of  the  limestones  and  shales  fur- 
nishing us  with  shells,  which,  from  their  form,  evidently 
lived  in  fresh  water ;  while  no  marine  forms  are  found 
with  them.  Land-snails  for  the  first  time  appear. 

Among  marine  shells,  the  productus,  of  which  Fig.  15 
represents  a  specimen  from  the  carboniferous       Fig<  ^ 
limestone,  Derbyshire,  England,  is  one  of  the 
most  common.      We  find  the  first  of  this 
family  in  the  Silurian  formation,  and  they  do 
not  pass  beyond  the  Permian.      More  than 
sixty  species  are  known :  most  of  them  be-  Produf0t^.yridl 
long  to  the  carboniferous. 

The  spirifer  (Fig.  16)  is  a 
shell  having  internal  calcare- 
ous spires  extending  from  the 
centre  of  the  shell  outward: 
from  these  it  receives  its  name. 
Many  species  of  this  family 
are  found  in  the  Silurian  and 
Devonian.  The  one  repre- 
sented is  from  the  carbonifer- 
ous limestone  of  Kildare,  near  Dublin,  Ireland. 


Fig.  16. 


Spirifer  pinguia. 


142  LECTURES  ON  GEOLOGY. 

Cephalopoda  are  not  as  common  as  they  were   dur- 
ing the  two  previous  periods ;  but  some  specimens  of 
Fig.  17.  the  orthoceras,  nautilus,  and  goniatite 

(Fig.  17),  are  occasionally  met  with* 
The  goniatite,  from  the  Greek  gonia, 
"  an  angle,"  derives  its  name  from  the 
angular  division  between  the  chambers. 
A  hundred  and  fifty  species  have  been 
described  from  the  Devonian  formation. 
About  thirty  species  of  orthoceratites  are  described 
from  the  English  carboniferous  beds ;  and  no  species 
has  yet  been  discovered  in  any  more  recent  forma- 
tion. 

Trilobites  were  few  in  number,  and  approaching  utter 
extinction :  it  is  very  rare  that  a  specimen  is  found  in 
the  coal-measures ;  and  above  this,  it  is  said,  no  specimen 
has  yet  been  discovered.  The  wings  of  insects  have 
been  found  in  Germany,  England,  and  the  United  States  ; 
and  from  them  we  learn  that  dragon-flies,  ants,  locusts, 
and  cockroaches  may  boast  of  a  very  high  antiquity. 
People  talk  about  tracing  their  ancestry  to  the  Norman 
Conquest ;  but  'what  is  that,  when  a  gentleman-beetle 
might  trace  his  to  a  time  when  Normandy  was  not,  and 
the  rock  had  yet  to  be  made  of  which  it  was  to  be 
formed  1 

Centipedes,  or  thousand-legged  worms,  have  been  found 
in  Nova  Scotia,  which  had  burrowed  into  a  sigillaria 
trunk. 

Fish  remains  are  abundant.  I  have  seen  thousands  of 
'  teeth  and  bones  on  sandstone  slabs  formed  at  the  bot- 
tom of  some  sea  then  covering  Northern  Ohio.  All  the 
fish  of  this  period,  as  well  as  those  of  the  Devonian  and 
upper  Siluri?n,  possessed  vertebrated  tails;  that  is,  the 
back-bone,  or  the  cartilage  which  occupied  its  place, 


LECTURES  ON  GEOLOGY.  143 

was  prolonged  into  the  tail,  —  a  peculiarity  which  we  now 
see  in  the  bony  pike,  shark,  and  sturgeon,  living  repre- 
sentatives of  a  very  ancient  type.  In  nearly  all  cases, 
this  made  a  one-sided  tail. 

In  the  younger  rocks  we  find  the  lop-sided  fishes,  or 
those  with  heterocercal  tails,  become  fewer  in  number, 
and  the  homocercal  fishes,  or  those  with  equal-lobed  tails, 
take  their  place  ;  so  that,  as  Agassiz  has  observed,  "  the 
progress  of  the  ages  is  marked  in  the  tails  of  the  fishes." 

Many  large  fish  belonging  to  the  genus  megalichthys 
(from  the  Greek  megas,  "  large,"  and  ichtJius, "  fish  ")  have 
been  found  in  the  carboniferous  strata  of  Edinburgh, 
Leeds,  Manchester,  and  other  localities  in  Scotland  and 
England.  These  fish  combined  many  of  the  characters 
of  a  true  fish  with  many  and  striking  resemblances  to 
reptiles.  The  teeth,  more  especially,  resemble  those  of 
crocodiles.  One  tooth  was  found  measuring  nearly  four 
inches  in  length,  and  nearly  two  inches  in  breadth  at  the 
base.  The  large  teeth  were  accompanied  by  small  ones, 
alternating  with  them,  and  distributed  over  the  whole  of 
the  inside  of  the  mouth.  The  teeth  are  cone-shaped,  and 
have  a  conical  hollow  at  the  base,  in  which  the  next 
tooth  is  prepared,  so  that  these  necessary  implements 
may  never  be  wanting :  the  same  provision  is  found  in 
the  teeth  of  reptiles. 

The  scales  of  the  megalichthys  are  formed  of  enamel, 
having  a  most  brilliant  lustre  :  they  are  generally  angu- 
lar, but  sometimes  rounded.  Their  rounded  scales  have 
been  found  five  inches  in  diameter. 

In  1852,  Professors  Dawson  and  Lyell  discovered  in 
the  coal-measures  at  Joggins,  on  the  Bay  of  Fundy,  the 
bones  of  two  small,  frog-like  reptiles,  and  the  shell  of  a 
land-snail,  "  in  the  interior  of  an  erect  tree,  mingled  with 


144  LECTURES  ON  GEOLOGY. 

the  sand,  decayed  wood,  and*  fragments  of  plants  which 
had  fallen  into  it  after  it  became  hollow."  Since  that 
time,  Professor  Dawson  has  discovered  another  fossil 
stump,  containing  the  remains  of  four  small  reptiles,  a 
centipede,  and  a  land-snail.  In  all,  there  were  four  spe- 
cies of  reptiles  in  these  two  stumps.  How  little  we  know 
of  the  numerous  forms  of  life  that  must  have  swarmed 
in  those  old  carboniferous  swamps  ! 

In  the  coal-measures  of  Bavaria,  many  fossil  remains 
have  been  found  of  an  animal  styled  the  archegosaurus, 
or  first  lizard ;  its  namer  supposing  it  to  be  the  oldest 
form  of  reptile.  Professor  Owen,  the  highest  living 
authority  on  these  subjects,  regards  it  as  a  transitional 
form  between  the  frogs  and  the  ganoidal  fishes.  "  It 
affords,"  says  he,  "  the  most  exemplary  instance  of  a 
transitional  form,  on  the  derivative  hypothesis,  of  an  air- 
breather  from  a  water-breather." 

Four  new  genera  of  reptiles  have  been  recently  found 
in  the  coal-beds  of  the  Jarrow  Colliery,  Kilkenny,  Ire- 
land. One  of  them  was  a  reptile  nearly  seven  feet  long. 
They  are  labyriniJiodonts,  which  were  very  numerous 
after  this,  and  attained  a  gigantic  size.  I  shall  refer  to 
them  again. 

To  obtain  coal  in  this  country  is  generally  an  easy 
matter,  cropping  out,  as  it  does,  on  the  banks  of  so  many 
streams.  Many  beds  of  it  may  be  seen  on  the  Penn- 
sylvania Central  Railroad,  on  the  western  slope  of  the 
Alleghanies,  on  the  banks  of  the  Alleghany  River,  and 
on  the  Ohio,  as  well  as  on  various  streams  of  Ohio  and 
Virginia.  Nothing  more  is  necessary  in  such  cases  than 
for  the  miner  to  "  drive  "  into  the  bank,  bring  out  the 
coal,  and  drop  it  into  the  flatboat  moored  immediately  be- 
neath ;  while  the  same  level  by  which  the  coal  is  brought 
out  serves  to  drain  the  mine  of  water. 


LECTURES  ON  GEOLOGY.  145 

In  England,  and  on  the  continent  of  Europe,  however, 
the  process  for  obtaining  coal  is  a  much  more  difficult 
one ;  all  the  coal  that  could  be  obtained  easily  having 
been  long  since  exhausted.  The  first  thing  to  be  done 
is  to  discover  where  tiie  coal  lies  ;  which  is  no  easy 
matter.  For  this  purpose,  boring  is  necessary,  as  for 
oil.  A  steel  drill  about  four  inches  in  diameter  is  lifted, 
dropped,  and  turned,  until  a  hole  of  equal  size  is  made 
down  to  the  coal-bed,  whose  presence  and  thickness  can 
thus  be  ascertained.  If  a  bed  two  feet  thick,  it  will 
not  pay  to  work ;  and  down  goes  the  drill  to  a  second, 
perhaps  a  hundred  feet  deeper.  This  is  three  feet 
thick  j  but  that  is  not  thick  enough  for  profitable  work- 
ing ; .  so  down  to  a  third.  This  is  six  feet  thick.  Now 
the  work  of  sinking  a  shaft  commences  ;  for  a  hole  must 
be  made  large  enough  to  bring  up  the  black  treasure 
discovered. 

The  miners  dig,  therefore,  a  well-like  shaft  ten  or 
twelve  feet  in  diameter ;  but,  before  going  far,  water 
rushes  in  more  rapidly  than  they  can  bail  it  out.  A 
steam-engine  is  necessary  to  pump  out  this  water,  and 
to  keep  the  mine  clear  when  it  is  in  operation.  Another 
one  is  needed  to  hoist  up  the  rock  and  coal  j  and  then 
the  work  goes  on  with  increased  speed.  When  the 
coal  is  reached,  and  galleries  are  cut  in  it  to  obtain 
the  coal,  the  miners  soon  experience  a  lack  of  pure  air, 
—  especially  after  blasting  with  gunpowder.  For  the 
purpose  of  supplying  the  mine  with  pure  air,  a  second 
shaft  is  generally  sunk,  sometimes  at  a  distance  of  half 
a  mile  from  the  first;  galleries  are  made  underground 
from  one  shaft  to  the  other ;  and  at  the  bottom  of  the 
second  a  large  furnace  is  erected,  and  a  fire  made, 
which  is  constantly  supplied  with  coal.  This  causes  a 
10 


146  LECTURES   ON  GEOLOGY. 

current  of  air  to  rise  to  the  'surface  up  this  shaft,  which 
is  called,  on  this  account,  the  "  up-cast  shaft."  Down 
the  other  shaft,  which  is  called  the  "  down-cast  shaft," 
goes  the  pure  air,  regulated  by  trap-doors  in  the  gal- 
leries, sweeping  through  the  mine,  carrying  off  the 
impurities  from  every  portion  to  the  furnace,  and  so  to 
the  surface. 

In  Great  Britain,  there  are  about  twelve  thousand 
miles  of  coal-lands  ;  and  more  than  eighty  million  tons  of 
coal  are  taken  out  every  year.  It  has  been  calculated, 
that,  at. the  present  rate  of  use,  the  coal  of  this  island 
will  not  last  more  than  two  hundred  years.  Already  it 
has  become  a  serious  question  in  England,  "  What  shall 
we  do  when  the  coal  is  gone  ?  " 

In  tin?  United  States,  there  are  about  one  hundred 
and  twenty  thousand  square  miles  underlaid  by  known 
workable  coal-beds,  besides  what  remains  yet  to  ,-be 
discovered.  With  this  immense  stock  of  fuel  in  our 
cellar,  what  a  future  there  will  be  for  the  house  of 
Jonathan  !  Long  will  it  be  before  the  question  will  be 
seriously  asked  in  this  country,  "  How  long  will  our 
coal  last  ?  " 

Although  bituminous  coal  is  generally  the  product  of 
vegetation,  it  is  not  invariably  so.  In  Albert  County, 
New  Brunswick,  there  is  a  large  fissure,  in  places  seven- 
teen feet  wide,  which  is  filled  with  a  jet-black,  shining 
coal.  It  has  been  worked  to  a  depth  of  seven  hundred 
and  fifty  feet,  and  apparently  continues  to  a  much 
greater  depth.  This  coal  is  now  acknowledged  to  be 
solidified  petroleum ;  and  is  therefore,  as  I  think,  an 
animal  product. 

All  petroleum-coal  that  I  have  seen  and  heard  of 
occupies  veins,  generally  perpendicular,  instead  of  hori- 


LECTURES  ON  GEOLOGY.  147 

gontal  beds.  There  is  one  in  Ritchie  County,  Western 
Virginia,  another  in  Scotland,  several  in  Cuba,  and  others 
which  I  discovered,  partly  in  Utah,  and  partly  in  Colo- 
rado, on  White  River.  The  coal  of  these  ,can  scarcely 
be  distinguished  in  any  way  from  the  Albertite  of  New 
Brunswick.  The  largest  deposit  forms  a  perpendicular 
vein  about  three  feet  wide,  which  we  traced  for  more 
than  three  miles.  In  the  same  region  is  a  bed  of  highly 
bituminous  shale,  equal  to  cannelite,  which  I  found  at 
various  points;  indicating  that  it  extends  over  twelve 
hundred  square  miles.  The  bituminous  deposits  of  this 
country  are  not  all  discovered  yet.  We  have  sleeping 
servants  under  ground  that  future  generations  must 
waken. 

THE  PERMIAN  FORMATION. 

In  the  eastern  part  of  European  Russia,  and  princi- 
pally in  that  part  of  it  which  constituted  the  ancient 
kingdom  of  Permia,  are  limy  flagstones,  magnesiau 
limestones,  bituminous  shales,  and  red  and  green  sand- 
stones ;  some  of  these  beds  sufficiently  impregnated 
with  copper  to  pay  for  working.  They  cover  an  extent 
of  country  twice  as  large  as  France ;  and,  from  their 
occurrence  in  and  around  Perm  more  extensively  than 
in  any  other  explored,  locality,  the  formation  to  which 
they  belong,  which  is  next  above  the  carboniferous, 
is  styled  the  Permian  formation. 

This  is  the  highest  or  most  recent  paleozoic  formation. 
Paleozoic  means,  literally,  "  old  life  ;"  and  the  paleozoic 
rocks  are  those  of  the  Silurian,  Devonian,  Carboniferous, 
and  Permian  formations,  containing  the  oldest  animal 
and  vegetable  forms.  The  fossils  found  in  the  Permian 


148  LECTURES  ON  GEOLOGY. 

rocks  more  closely  resemble*  those  found  in  the  rocks 
below,  or  those  that  are  older  than  the  Permian,  than 
those  that  are  found  in  the  younger  formations. 
M.  Pictet  shows  that  fifty-six  generic  forms  out  of  a 
hundred  pass  from  the  earlier  periods  to  the  Permian  ; 
and  hence  the  propriety  of  placing  this  with  the  old-life 
formations.  Murchison  says,  "  In  ascending  above  the 
highest  Permian  deposits,  the  geologist  takes  a  sudden 
and  final  leave  of  nearly  every  thing  in  nature  to  which 
the  words  '  primary,'  '  primeval/  or  '  paleozoic/  have 
been  or  can  be  applied.'7 

Caution  is  necessary,  however,  in  accepting  this 
statement.  Thirty-three  out  of  a  hundred  generic  forms 
belonging  to  the  older  periods  are  found  in  the  trias, 
the  formation  immediately  above  the  Permian  ;  and, 
when  all  the  Permian  and  triassic  beds  are  known,  we 
shall  find,  as  in  all  other  formations,  that  life-forms 
change  almost  insensibly  from  the  one  to  the  other. 
Thus  he  says,  in  his  last  anniversary  address  as  Presi 
dent  of  the  London  Geological  Society,  "  We  have  been 
obliged  to  give  up  the  theory  of  great  breaks  between 
successive  formations,  as  we  find  a  gradual  passage 
from  one  geological  formation  to  another,  evidenced  by 
a  gradual  dying-out  of  the  pre-existing  forms  of  life, 
and  the  gradual  introduction  of  newer." 

Owen  also  says,  "  The  sum  of  the  animal  species  at 
each  successive  geological  period  has  been  distinct  and 
peculiar  to  such  period.  Not  that  the  extinction  of 
such  forms  or  species  was  sudden  or  simultaneous :  the 
evidences  so  interpreted  have  been  but  local.  Over 
the  wider  field  of  life  at  any  given  epoch,  the  change 
has  been  gradual,  and,  as  it  would  seem,  obedient  to 
some  general,  continuously  operative,  but  -as  yet  ill- 
comprehended  law." 


LECTURES 'ON  GEOLOGY.  149 

In  the  Permian  rocks  of  G-ermany  there  is  a  large 
development  of  magnesian  limestone,  underlaid  by  dark 
bituminous  shales  highly  charged  with  sulphuret  of 
copper,  which  is  called  IZupfer-schiefer,  or  copper-slate. 
These  slates  have  been  worked  for  many  years  for  the 
copper  that  they  contain;  and  fossil  fishes  have  been 
found  in  them  in  great  abundance. 

The  copper-slate  of  Mansfield  has  a  thickness  varying 
from  one  and  a  half  to  two  feet,  and  is  worked  in  numer- 
ous mines  by  a  process  called  "  crooked-stick  work,"  — 
the  miners  crawling  and  working,  lying  upon  their  sides, 
in  cavities  eighteen  or  twenty  inches  high;  the  roof 
over  them  supported  by  pieces  of  bent  timber  or 
crooked  sticks. 

The  Permian  formation  is  well  developed  in  the  north 
of  England,  where  it  consists  of  magnesian  limestones 
and  sandstones,  having  a  thickness  of  one  thousand  feet. 
The  harder  varieties  of  the  Permian  limestones  make 
excellent  building-material ;  and  the  new  Houses  of  Par- 
liament, in  London,  are  constructed  of  this  limestone, 
which  is  thought  to  be  the  best  building-stone  of 
England.  Permian  rocks  have  recently  been  discovered 
west  of  the  Mississippi  River,  principally  in  Kansas ; 
but  we  have  no  knowledge  of  their  precise  bound- 
ary. They  consist  of  limestones,  sandstones,  and  shales ; 
and  their  greatest  thickness  is  less  than  a  thousand 
feet. 

The  plants  of  this  period  belong  to  genera  that  are 
common  in  the  coal-measures,  but  are  either  wanting  or 
very  rare  in  the  formations  above.  Silicified  stems  of 
ferns  have  been  found  in  Saxony,  and  silicified  trunks 
of  coniferous  or  cone-bearing  trees  in  England. 

The    tnlobite    has  not  been  found  in  the  Permian. 


150  LECTURES  ON  GEOLOGY. 

This  family  came  into  existence  early,  attained  its 
greatest  development  about  the  middle  of  the  Silurian 
period,  diminished  in  size  and  number  in  the  Devonian, 
was  reduced  to  a  few  small  species  in  the  carboniferous, 
and  with  the  Permian  seems  to  have  died  out  to  appear 
no  more.  The  limulus,  an  animal  somewhat  resembling 
the  trilobite,  seems  to  have  taken  its  place.  It  appeared 
in  the  coal-measures :  large  species  have  been  found  in 
the  Permian  beds  of  Russia,  and  some  species  still  exist 
in  our  present  oceans.  The  king-crab,  or  horse-shoe 
crab,  is  a  familiar  example. 

Between  fifty  and  sixty  species  of  fish  have  been 
found  in  this  formation,  some  of  which  are  identical 
with  those  found  in  the  carboniferous  formation.  All 
these  fish  have  heterocereal  tails.  In  one  locality  in 
Ireland,  a  small  species  is  found  in  such  numbers,  that 
more  than  two  hundred  have  been  counted  on  a  slab 
two  feet  square.  The  ichthyolites,  or  fossil  fishes,  oC 
the  Kupfer-scliiefer  of  Germany,  may  be  found  in  al- 
most every  museum  of  Europe.  These  specimens,  says 
Mantell,  are  splendidly  invested  with  copper  pyrites, 
and  their  scales  have  the  appearance  of  burnished 
gold. 

Many  remains  of  reptiles  have  been  found  in  the 
Permian  deposits ;  the  first  by  Dr.  Spener,  a  physician 
at  Berlin,  in  1710.  It  was  obtained  from  a  copper-mine 
in  Germany,  at  a  depth  of  one  hundred  feet.  Other 
specimens  have  been  discovered  since.  They  were 
aquatic  reptiles,  furnished  with  sixty-eight  sharp,  conical 
teeth ;  and  probably  fed  upon  the  fishes  which  we  know 
flourished  in  the  waters  which  deposited  the  copper 
slates  of  Germany. 

Some  remains  of  reptiles  similar  to  these  have  been 


LECTURES  ON  GEOLOGY.  151 

found  near  Bristol,  in  England,  and,  according  to  Dr. 
Emmons,  in  the  Permian  strata  of  the  Chatham  coal- 
field, in  North  Carolina. 

"  The  old  must  pass  away  that  the  new  may  come 
in."  So  pass  away,  with  the  Permian  formation,  old 
oceans,  old  islands,  old  shells,  old  fishes.  As  the  stars 
sink,  one  by  one,  in  the  west,  and  new  stars  rise  in  the 
east,  to  be  succeeded  by  the  dawn,  and  then  the  day  ; 
so,  through  the  night  of  the  past,  sank  the  old  life-forms, 
and  were  succeeded  by  the  new,  approaching  nearer 
and  nearer  to  the  dawn  of  that  day  in  whose  morning 
we  live. 

SECONDARY  PERIOD. 

AGE    OF  REPTILES. 

Trias,  or  New  Red  Sandstone.  —  The  secondary  for- 
mation is  divided  by  Lyell  into  five  divisions :  — 

1.  TRIAS,  OR  NEW  RED  SANDSTONE. 

2.  LIAS. 

3.  OOLITE. 

4.  WEALDEN. 

5.  CHALK,  OR  CRETACEOUS. 

The  trias,  or  new  red  sandstone,  derives  its  name 
of  trias  from  the  fact,  that,  in  Germany,  it  consists  of 
three  different  groups  of  rocks,  called  Bunler  Sandstein, 
or  colored  sandstone,  Muschelkalk,  or  mussel-chalk,  and 
Keuper,  which  is  supposed  to  be  a  miner's  term,  used 
to  designate  a  group  of  red  and  green  marls,  and  shales. 

It  receives  its  name  of  new  red  sandstone  from  the 
fact,  that,  in  England  and  in  this  country,  it  is  formed 


152  LECTURES   ON  GEOLOGY. 

principally  of  red  sandstones;  and  to  distinguish  be- 
tween  them  and  the  old  red  sandstone,  belonging  to 
the  Devonian  formation,  it  is  termed  the  new  red  sand- 
stone. 

This  formation  has  received  the  name  of  saliferous 
formation,  from  the  great  abundance  of  salt  associated 
with  its  beds.  Salt  is  not  by  any  means  confined  to 
the  new  red  sandstone,  but,  in  Europe,  is  found  more 
commonly  connected  with  rocks  of  this  age  than  with 
any  other. 

At  Droitwich,  England,  one  salt-spring  yields  a  thou- 
sand tons  of  salt  a  week.  In  boring  for  this  brine,  they 
pass  through  four  layers  of  salt,  eighty-five  feet  in 
aggregate  thickness.  The  brine  is  so  strong,  that  it 
yields  one-fourth  of  its  weight  in  salt.  In  Cheshire, 
there  is  a  bed  of  salt  eighty-five  feet  thick,  then  a  bed 
of  marl  thirty  fe*et  thick,  below  which,  is  a  second  bed  of 
salt  one  hundred  and  six  feet  thick. 

At  Cardona,  in  Spain,  there  is  a  salt-mountain  several 
hundred  feet  high.  At  the  foot  of  the  mountain  is  a 
rivulet,  which  in  rainy  seasons  swells  into  a  river,  and 
carries  down  so  much  salt  as  to  destroy  the  fish.  "  Noth- 
ing," says  Count  Laborde,  "  can  be  more  beautiful  than 
the  appearance  of  this  mountain  at  sunrise.  Besides 
the  beautiful  form  which  it  presents,  it  appears  to  rise 
above  the  river  like  a  mountain  of  precious  gems,  dis- 
playing the  varied  colors  of  the  rainbow." 

The  chief  repository  of  salt  is  in  Poland.  Mines  have 
been  worked  ten  miles  from  Cracow  to  a  depth  of  more 
than  one  thousand  feet.  These  mines  are  entered  by 
eleven  shafts,  with  galleries  at  five  different  levels,  lead- 
ing to  a  labyrinth  of  passages  and  excavations,  whose 
total  length  is  two  hundred  and  seventy  miles.  Chambers 


LECTURES  ON  GEOLOGY.  153 

have  been  dug  out  one  hundred  and  fifty  feet  high. 
One  was  fitted  up  as  a  chapel,  and  dedicated  to  St. 
Anthony:  it  contained  an  altar,  statues,  columns,  and 
pulpit,  all  of  salt.  Dr.  Darwin,  in  his  "  Botanic  Garden," 
referring  to  this  mine,  says,  — 

"  Thus  caverned  round  in  Cracow's  mighty  mines, 
With  crystal  walls  a  gorgeous  city  shines  ; 
Scooped  in  the  briny  rock,  long  streets  extend 
Their  hoary  course,  and  glittering  domes  ascend; 
Down  the  bright  steeps,  emerging  into  day, 
Impetuous  fountains  burst  their  headlong  way, 
O'er  milk-white  vales  in  ivory  channels  spread, 
And,  wandering,  seek  their  subterranean  bed." 

The  question  very  naturally  presents  itself,  Whence 
came  these  enormous  masses  of  salt  ?  There  was  a  time 
when  they  were  not,  and  a  time  when  they  began  to  be. 
Some  have  suggested,  that  salt  being  in  some  places  a 
volcanic  product,  salt-springs  flowing  in  the  neighbor- 
hood of  many  volcanoes,  these  saline  deposits  may  have 
been  formed  at  some  past  time,  during  a  period  of  great 
volcanic  activity ;  the  salt  carried  into  lake-basins,  and 
there  evaporated. 

Their  origin  has  also  been  referred  to  the  evaporation 
of  the  water  of  ordinary  salt-lakes,  leaving  the  salt  as 
a  sediment.  All  lakes  having  rivers  flowing  into  them, 
and  no  outlet  for  their  waters,  are  salt-lakes.  All  rivers 
contain  more  or  less  salt :  this,  flowing  into  a  basin,  is 
constantly  increasing;  for,  though  the  water  is  evaporat- 
ed, the  salt  is,  of  course,  left  behind.  In  time,  so  much 
salt  is  deposited  in  the  lake,  that  the  water  cannot  hold 
any  more  in  solution,  and  it  settles  to  the  bottom  by  its 
weight.  Put  a  spoonful  of  salt  into  a  cup  of  water,  the 


154  LECTURES  ON  GEOLOGY. 

water  will  dissolve  it  readily  ;  put  in  another,  the  water 
will  dissolve  it  less  readily;  by  adding  still  more,  the 
water  at  last  can  take  up  no  more  salt,  and  it  lies  in  a 
solid  form  at  the  bottom  of  the  cup.  The  River  Jordan 
has  many  salt-springs  flowing  into  it,  and  is  therefore 
constantly  carrying  salt  into  the  Dead  Sea,  which  is 
thirteen  hundred  feet  below  the  level  of  the  Mediter- 
ranean, and  consequently  has  no  outlet.  On  sounding  it, 
Lieut.  Lynch  brought  up  crystals  of  salt  from  a  depth 
of  one  hundred  and  sixteen  fathoms,  showing  that  such  a 
process  is  now  going  on  there.  Lake  Indersk,  in  Siberia, 
has  a  crust  of  salt  at  the  bottom,  hard  as  a  stone,  and 
perfectly  white.  There  are  salines  in  New  Mexico,  old 
lake-beds,  five  or  six  miles  in  circumference,  at  the 
bottom  of  which  are  beds  of  salt  of  unknown  depth. 

It  is  said  that  four  gallons  of  the  water  of  the  Great 
Salt  Lake,  in  Utah,  will  make  one  gallon  of  salt ;  and  if 
the  Bear  and  Jordan  Rivers,  which  flow  into  it,  should 
be  cut  off  by  any  natural  convulsion,  it  would  form  an 
immense  salt-pan,  the  water  would  evaporate,  and  there 
would  be  one-fourth  as  much  salt  left  at  the  bottom  as 
there  is  now  depth  of  water  in  the  lake. 

We  can  readily  see,  then,  how  some  salt-beds  could 
be  produced.  But  we  have  facts  which  point  to  the 
ocean  as  the  source  of  some  saline  deposits.  In  the 
Polish  salt-mines,  bivalve  shells  and  the  claws  of  crabs 
are  met  with  in  the  marls  associated  with  the  salt- 
beds.  In  Bolivia,  sea-shells  are  found  with  salt-beds, 
which  are  more  than  six  thousand  feet  above  the  present 
sea-level. 

The  ocean  is  the  great  reservoir  of  salt,  and  has  been, 
^probably,  ever  since  it  existed.  Estimating  its  average 
depth  at  five  thousand  feet,  there  are  in  its  waters  thirty 


LECTURES   ON  GEOLOGY.  155 

thousand  million  of  millions  of  tons  of  salt.  Doubtless  a 
large  proportion  of  tke  salt  contained  in  the  earth's 
strata  came  originally  from  this  grand  reservoir.  The 
new  red  sandstone  period,  we  know,  was  one  of  unusual 
volcanic  activity.  That  mountain-ridge  of  greenstone 
in  Connecticut  and  Massachusetts,  of  which  Mount  Hoi- 
yoke  and  Mount  Tom  are  the  highest  portions,  is  believed 
to  be  of  this  age,  and  indicates,  to  some  extent,  the  size 
of  the  lavartorrents  of  that  time.  The  Palisades  on  the 
Hudson ;  the  trap  of  the  Island  of  Staffa,  in  which  Fin- 
gal's  Cave  has  been  hollowed ;  the  trap  forming  the 
Giant's  Caasway,  in  Ireland  ;  the  long  bed  of  trap  on 
the  shores  of  the  Bay  of  Fundy,  —  all  believed  to  have 
been  formed  during  this  age,  —  testify  how  fearfully 
the  Earth's  fires  raged  during  this  period,  and  how 
she  poured  out  her  boiling  tides. 

Imagine  an  arm  of  the  sea  twenty  miles  long,  ten  miles 
broad,  and  a  thousand  feet  deep,  cut  off  from  the  main 
body  by  an  eruption  of  lava,  which  flows  across  it.  The 
heat  produced  by  it  causes  the  water  to  boil  like  a  kettle 
on  a  fire,  as  the  recent  lava-flood  at  Hawaii  caused  the 
sea  to  boil.  The  water  is  evaporated,  and  twenty-seven 
feet  of  solid  salt  are  left  at  the  bottom;  for  in  one 
thousand  parts  of  sea-water  there  are  twenty-seven 
parts  of  salt.  If,  instead  of  being  a  thousand  feet  thick, 
it  had  been  four  or  five  thousand  feet,  the  salt-bed  pro- 
duced would  have  been  of  corresponding  thickness. 

But,  after  proceeding  so  iar,  the  question  arises, 
Where  did  the  sea  obtain  its  saltness  ?  For  man  is  an 
inquisitive  animal,  whose  questions  corner  at  last  the 
wisest.  There  was  a  time  when  the  ocean  was  not,  if 
we  have  read  aright  the  story  of  the  earth  which  the 
rocks  relate.  Where  was  the  salt  then  ?  Lieut.  Maury 


156  LECTURES  ON  GEOLOGY. 

thinks  that  the  sea  was  created  salt,  and  suggests,  that, 
had  it  been  otherwise,  the  present  animals  living  in  it 
could  have  had  no  existence ;  but  then,  I  suppose,  forms 
of  life  just  as  perfect  could  have  existed  in  it,  had 
it  been  fresh,  as  we  find  all  large  bodies  of  fresh  water 
tenanted  to-day.  Sir  Richard  Blackmore  asks,  "  What 
does  the  sea  from  putrefaction  keep  ? "  and  then  in 
answer  says,  — 

"  Should  it  lie  stagnant  in  its  ample  seat, 
The  sun  would  through  it  spread  destructive  heat. 
The  wise  Contriver,  on  his  end  intent, 
Careful  this  fatal  error  to  prevent, 
And  keep  the  waters  from  corruption  free, 
Mixed  them  with  salt,  and  seasoned  all  the  sea.'* 

We  may  excuse  the  poet  where  we  criticise  the  man  of 
science ;  but  I  should  like  to  ask  him  why  such  a  large 
body  of  water  as  Lake  Superior  is  fresh,  and  how  it  is 
preserved  from  putrefaction  ;  and  why  such  a  small  body 
of  water  as  the  Dead  Sea  is  so  salt,  so  highly  seasoned, 
that  it  would  seem  as  if  the  salt-cellar  had  been  dropped 
into  it. 

There  must  have  been  a  time  when  there  was  no  salt, 
the  elements  alone  existing  of  which  salt  is  a  combina- 
tion. The  chemist  informs  us  that  salt  is  chloride  of 
sodium,  or  a  union  of  chlorine  (a  heavy  gas,  being  two 
and  a  half  times  heavier  than  the  air  we  breathe)  and 
sodium  (a  light,  bright,  beautiful,  silvery  metal ;  so  light, 
that  it  will  float  en  the  surface  of  water).  By  burning 
sodium  in  chlorine  gas,  the  two  unite,  and  salt  is  tho  re- 
sult ;  or  it  may  be  produced  by  saturating  soda,  which  is 
the  oxide  of  sodium,  with  hydrochloric  acid,  arid  evap- 
orating to  dryness.  When,  at  an  early  period  of  the 
world's  history,  acids  distilled  from  the  clouds,  and  the 


LECTURES  ON  GEOLOGY.  157 

earth  was  a  grand  chemical  laboratory,  either  directly 
or  indirectly,  salt  was  produced  on  its  surface  with 
many  other  minerals;  and,  as  the  rains  fell,  all  that  were 
soluble  were  leached  into  the  hollows  of  the  globe,  and 
what  remain  unprecipitated  give  to  the  sea  its  saltness. 
The  sea  is  but  a  great  vessel  into  which  the  impurities 
of  the  land  have  been  drained :  and  many  of  our  geo- 
logical beds  are  but  those  impurities  in  a  compact  form, 
buried  generally  from  sight ;  both  land  and  water  bene- 
fited by  the  process,  —  that  is,  prepared  for  the  use  of 
higher  organic  forms. 

For  it  is  not  common  salt  alone  that  the  sea  contains, 
but  many  other  substances  mingled  with  it.  In  one 
hundred  parts  of  solid  matter  contained  in  the  water 
of  the  ocean,  there  are  of 

Common  salt,  or  chloride  of  sodium     .     .     .  78.61 

Chloride  of  potassium 1.34 

Chloride  of  magnesium 8.56 

Sulphate  of  lime,  or  gypsum 3.47 

Sulphate  of  magnesia,  or  Epsom  salt  .     .     .  6.42 

Carbonate  of  lime .27 

Of  residue  undetermined 1.33 

In  this  undetermined  residue,  bromine  and  iodine 
are  contained,  as  they  are  known  to  exist  in  sea-water. 

To  leach  these  saline  impurities  out  of  the  land  seems 
to  have  taken  a  long  time.  We  have  no  evidence  of  the 
existence  of  bodies  of  fresh  water  on  the  globe  until 
after  the  Silurian  period.  Not  till  we  arrive  at  the  De- 
vonian formation  do  we  discover  shells  whose  form  indi- 
cates that  they  were  fresh-water  inhabitants,  that  the 
rains  of  ages  had  at  last  purified  the  land,  and  fitted  it 
for  the  sustentation  of  life. 

With   salt,    we    generally   find    sulphate    of  lime,   or 


158  LECTURES  ON  GEOLOGY. 

gypsum,  associated.  .  This  is  the  case  in  England,  at 
Syracuse  in  New  York,  and  at  Grand  Rapids  in  Michi- 
gan ;  so  that  when  we  find  gypsum  we  look  for  salt, 
and  when  we  find  salt  we  look  for  gypsum,  in  the 
neighborhood.  When  gypsum  is  ground,  as  it  is  in 
mills,  like  corn,  to  a  fine  powder,  it  is  then  used  as  a 
fertilizer ;  and  is  on  many  lands  of  great  value,  as  farmers 
generally  know.  When  this  powder  is  exposed  to  a  heat 
of  about  two  hundred  and  thirty  degrees,  it  parts  with 
its  water  of  crystallization  (one-fourth  of  gypsum  being 
water),  and  becomes  a  dry  powder  called  plaster  of  Paris. 
This,  when  mixed  with  water  again  to  about  the  con- 
sistency of  cream,  returns  in  a  short  time  to  solid  -stone. 
It  is  of  the  greatest  value  on  this  account  for  making 
casts ;  and  dentists  and  artists  generally  make  great  use 
of  it.  The  plaster  casts  of  dogs,  monkeys,  and  men, 
carried  by  Italians  on  their  shoulders  through  our 
streets,  are  made  of  this  material ;  and  there  are  few 
halls  or  parlors  which  it  does  not  assist  in  decorating. 

It  is  a  sulphate  of  lime,  formed  by  a  union  of  sul- 
phuric acid  and  lime.  Sulphuric  acid  is  one  of  the 
products  of  volcanoes.  Streams  of  it  flowing  over  or 
through  limestone  rocks  would  dissolve  the  limestone 
most  rapidly,  and  form  sulphate  of  lime  ;  this,  carried 
into  lakes  or  the  ocean,  would  settle  by  virtue  of  its 
weight  to  the  bottom,  and  form  a  bed  of  gypsum.  In 
other  cases,  where  the  ocean  or  lakes  held  in  their 
waters  much  lime,  sulphuric  acid  poured  into  them 
would  change  this  lime  to  gypsum,  which  would  sink, 
and  form  a  bed.  Experiments  that  chemists  now  try 
on  a  small  scale,  Nature  tried  ages  before  on  the  grand- 
est scale,  and  with  the  most  important  results. 

The  new  red  sandstone  exists,  it  is  supposed,  in  the 


LECTUBES  ON  GEOLOGY.  159 

Connecticut  Valley,  from  the  north  of  Massachusetts  to 
Long-Island  Sound,  a  distance  of  one  hundred  and  ten 
miles,  with  an  average  breadth  of  twenty  miles.  An- 
other range  extends  from  Rockland,  on  the  Hudson 
River,  through  New  Jersey,  Pennsylvania,  and  part  of 
Virginia.  It  is  three  hundred  and  fifty  miles  long,  and 
from  five  to  thirty  miles  broad.  Several  other  ranges 
are  known  in  Virginia  and  North  Carolina.  It  is  evi- 
dent, that,  where  these  ranges  are,  valleys  once  existed 
parallel  to  each  other,  and  having  their  longest  direction 
from  north  to  south.  These  valleys  were  occupied  by 
water,  either  as  lakes,  estuaries,,  or  arms  of  the  sea  j 
receiving  sediment  continually  as  it  was  poured  in  from 
the  neighboring  hills,  either  as  pebbles  to  make  con- 
glomerates, coarse  sand  to  make  coarse  sandstone,  or 
fine  sand  to  make  the  fine-grained  sandstones. 

During  this  period,  we  know  these  valleys  were 
deepening ;  for  the  beds  are  from  three  to  six  thousand 
feet  thick,  slowly  sinking  and  slowly  filling  up  with 
sediment  as  age  after  age  passed  away. 

The  fossils  of  the  new  red  sandstone  are  not  abun- 
dant. One  reason  may  be,  that  sand  is  a  very  unfavora- 
ble material  for  the  preservation  of  fossils  5  for  in  the 
Valley  of  the  Connecticut  we  have  evidence  that  life 
during  this  period  abounded  in  numerous  forms,  though 
little  more  than  the  prints  of  their  feet  are  left  to  tell 
the  story  of  their  lives. 

Over  a  space  in  the  Connecticut  Valley  ninety  miles 
lonjy,  and  from  two  to  three  broad,  footprints  of  various 
animals  have  been  found  on  slabs  of  sandstone, — 
evidently  impressed  when  this  was  soft  mud  by  the 
shore.  They  were  first  discovered  by  Dr.  Deane,  and 
carefully  studied  by  Professor  Hitchcock,  who  thought 


160  LECTURES  ON  GEOLOGY. 

that  the  tracks  then  discovered  indicated  one  hundred 
and  nineteen  species  of  animals,  of  which  he  regarded 
thirty-one  as  birds,  seventeen  lizards,  eleven  frogs,  eight 
tortoises,  four  fishes,  twenty-six  articulates,  ten  bird- 
lizards,  and  five  marsupialoids,  or  animals  resembling 
those  mammals  that  have  a  poach  for  their  young,  such 
as  the  opossum. 

The  largest  of  the  bird-like  tracks  is  eighteen  inches 
long,  and  the  length  of  stride  from  two  and  a  half  to  five 
feet.  Professor  Hitchcock  calculated  the  height  of  the 
animal  at  twelve  feet,  and  its  weight  from  four  to  eight 
hundred  pounds.  From  the  depth  of  the  impression 
made,  the  animal  must  have  been  very  heavy.  I  have 
seen  one  track  which  holds  a  gallon  of  water. 

On  some  slabs  at  Turner's  Falls,  the  tracks  are  so 
abundant,  that  no  one  can  be  distinguished  from  another. 
They  look  as  we  may  see  a  muddy  road  after  a  flock  of 
sheep  has  passed. 

The  reptile-tracks  are  from  one-fourth  of  an  inch  to 
twenty-two  inches  in  length.  The  largest  reptile  seems 
to  have  been  a  kind  of  frog.  A  frog  twenty-two  inches 
long  would  be  a  monster ;  but  what  kind  of  a  frog  was 
that  whose  foot  was  twenty-two  inches  long,  and  from 
thirteen  to  fifteen  inches  wide  ?  Professor  Hitchcock 
thought  it  was  "  almost  as  heavy  as  an  elephant."  It 
was  web-footed,  and  the  front  feet  were  not  more  than 
one-third  as  large  as  the  hind  ones.  In  Amherst  cabi- 
net is  a  slab  thirty  feet  long,  on  which  are  eleven  of 
these  tracks. 

Another  reptile  was  a  lizard,  with  a  foot  fifteen  inches 
long,  having  a  heel  nearly  as  large  as  a  horse's  hoof,  and 
armed  with  a  stout  spur. 

Some  of  the  impressions  of  insects  are  so  fine,  that 


LECTURES  ON  GEOLOGY.  161 

they   require    a  magnifying    glass  to   bring   them   out 
distinctly. 

Certain  of  these  impressions,  which  were  regarded  as 
undoubted  bird-tracks,  prove  to  have  been  made  by 
some  remarkable  quadruped.  I  called  upon  Professor 
Hitchcock  during  his  last  illness,  and  found  him  in  bed, 
propped  up  with  pillows ;  while  upon  the  floor  before 
him  was  a  slab  containing  a  number  of  the  so-called 
bird-tracks.  The  tracks  of  what  every  one  might 
regard  as  a  bird  with  three  toes,  the  foot  three  or  four 
inches  long,  were  plainly  visible  on  one  portion  of  the 
slab.  But,  on  following  the  tracks  along,  the  animal  had 
rested ;  and  there  was  the  impression  of  its  long  heels, 
making  its  track  sixteen  inches  long;  while  in  front  of 
them  were  marks  made  by  small  fore-feet  that  had  just 
touched  the  ground,  while  behind  was  a  spot  on  the 

Fig.  18. 


Anomcepus  major. 


slab  where  the  tail  had  rested.     Fig.  18  represents  a 
portion   of  this   slab,  which  is  now  in  the  ichnological 
cabinet  at  Arnherst.     If  a  bird,  then,  it  had  four  feet, 
11 


162  "LECTURES   ON  GEOLOGY. 

and  a  tail  like  a  lizard.  And  what  kind  of  a  bird  could 
that  be  ?  Professor  Hitchcock  said,  that,  in  his  opinion, 
some  of  the  tracks  were  made  by  four-footed  birds 
having  some  resemblance  to  mammals  ;  while  others 
were  made  by  batrachian,  or  frog-birds.  He  says  in  one 
published  statement,  "  I  must  believe  that  these  animals 
combined  characters  now  found  distributed  among  birds, 
lizards,  batrachians,  and  perhaps  mammalia." 

Only  by  slow  degrees  did  life  mount  and  fly.  Prone 
on  the  water  at  first  it  lay,  or  crawled  upon  the  ground ; 
then,  elevated  slightly  above  it,  the  first  reptiles  crept. 
The  fore-feet  then  were  elevated,  and  the  hind-feet 
alone  were  employed  for  progression.  The  fore-feet 
became  small  by  disuse  ;  and  it  is  not  unreasonable  to 
suppose  that  from  these,  eventually,  membranous  Wings 
were  developed,  and  feathers  completed  the  bird.  True 
birds,  probably,  existed  during  this  period,  if  not  pre- 
viously. 

Strange  glimpses  of  the  by-gone  world  and  its  remark- 
able inhabitants  these  footsteps  of  ;the  new  red  sand- 
stone give  us.  Where  the  beautiful  Valley  of  the  Con- 
necticut is,  the  cultivated  field,  and  the  crowded  city, 
an  arm  of  the  ocean  was,  with  its  low,  broad,  flat, 
muddy  shore,  at  times  overflowed  by  the  waves. 

It  is  early  morning ;  and  the  fog  slowly  rises  from  the 
land,  unveiling  a  picture  that  dazzles  us  with  its  un- 
rivalled beauty.  Over  the  eastern  hills  appears  the 
red  sun,  larger  and  fierier  than  to-day;  the  pine-like  treea 
upon  the  mountain-tops  waving  their  lordly  crests. 
Stretching  away  to  a  long  'bay  or  gulf  is  a  slope  over- 
grown with  palm-like  and  luxuriant  tropical  trees,  from 
which  dangle  in  the  air,  and  stretch  from  bough  to 
bough,  vines  clad  with  flowers  of  brilliant  dye. 


LECTURES  ON  GEOLOGY.  163 

On  the  shore  of  the  bay  is  a  low;  flat  beach,  fringed 
on  the  land-side  with  broad-leafed  reeds  with  tufted 
tassels.  This  beach  is  from  two  to  three  miles  wide, 
composed  of  fine  micaceous  sand,  at  times  covered  by 
the  high  tide,  and  at  times  baking  in  the  sun's  hot  ray. 

But  what  of  the  inhabitants  of  this  old  world,  —  this 
world  beyond  a  thousand  floods?  Here  they  come, 
crawling,  hopping,  stalking,  down  to  the  shore,  some  of 
them  as  tall  as  young  giraffes,  and  with  bodies  as  large 
as  oxen.  Down  they  move  in  constant  procession  across 
the  sands  to  fish  in  the  morning  light.  The  water  is 
alive  with  fish,  frogs,  and  nondescript  reptiles,  swim- 
ming, crawling,  diving,  and  filling  the  air  with  their  din, 
—  that  din  made  more  horrible  as  these  gigantic  waders 
fill  their  crops  with  the  crawling  brood. 

In  "  The  Principles  of  Geology,"  Lyell  gives  us  the 
key  to  these  impressions  on  the  sandstones  of  the  Con- 
necticut Valley.  "  When  examining,  in  1842,  the  exten- 
sive mud-flats  of  Nova  Scotia,  which  are  exposed  at  low 
tide  on  the  borders  of  the  Bay  of  Fundy,  I  observed 
not  only  the  footprints  of  birds  which  had  recently 
passed  over  the  mud,  but  also  very  distinct  impres- 
sions of  raindrops.  The  sediment  with  which  the  waters 
are  charged  is  extremely  fine,  being  derived  from  the 
destruction  of  cliffs  of  red  sandstone  and  shale ;  and, 
as  the  tides  rise  fifty  feet  and  upwards,  large  areas 
are  laid  dry  for  nearly  a  fortnight  between  the  spring 
and  neap  tides.  In  this  interval,  the  mud  is  baked  in 
summer  by  a  hot  sun,  so  that  it  solidifies,  and  becomes 
traversed  by  cracks  caused  by  shrinkage.  Portions  of 
the  hardened  mud  between  these  cracks  may  then  be 
taken  up,  and  removed  without  injury." 

I  have  taken  up  many  of  these  near  Windsor,  in  the 


164  LECTURES  ON  GEOLOGY. 

Bay  of  Fundy,  containing  impressions  of  dogs  and  men 
that  had  walked  over  the  spot,  and  prints  of  raindrops 
identical  with  those  found  on  new  red  slabs,  so  common 
in  many  localities.  It  is  a  marvellous  fact,  that  while 
millions  of  men  have  lived,  and  striven  their  best  to  leave 
an  enduring  record  behind  them,  but  have  been  swal- 
lowed in  Oblivion's  never-to-be-satisfied  maw,  the  rain  of 
millions  of  years  ago,  falling  all  unconsciously  upon  the 
sinking  sand,  —  the  very  types  of  all  that  is  perishable,  — 
has  left  a  record  so  enduring,  that  we  read  it  now,  and 
can  tell  by  the  shape  of  those  rain-pits  the  direction  of 
the  wind  that  blew  so  long,  long  ago.  I  have  seen  a 
brick  from  Nineveh,  more  than  two  thousand  years  old, 
with  the  impression  of  the  foot  of  a  dog  upon  it,  made, 
evidently,  while  it  was  yet  soft  as  it  lay  in  the  sun  to  dry. 
I  have  a  brick  in  my  possession  taken  from  the  chimney 
of  an  old  house,  which  bears  a  very  distinct  impression 
of  a  hen's  foot.  Such  impressions  might,  of  course,  be 
preserved  for  millions  of  years,  as  those  of  the  Connec- 
ticut Valley  have  been. 

Near  Richmond,  Ya.,  there  are  several  seams  of  good 
coal   in  this  formation.     There  are  also  others  in  North 
Fig<  19>  Carolina ;    and   they    show 

that  coal-making  did  not 
end  with  the  carboniferous 
period. 

Many  of  the  plants  were 
allied  to  those  of  the  coal- 
measures.  Calamites,  equi- 
seta,  and  ferns  are  the  most 
common.  Among  shells, 
cerate  nodosus.  spirifers  and  prodacti  are 

abundant ;  and,  among  cephalopods,  the  ammonite  family 


LECTURES  ON  GEOLOGY.  165 

begins  to  rise  into  importance.  Fig.  19  represents  one 
genus  of  this  family,  from  the  muschelkalk  of  Lune- 
ville,  France.  'Fossil  fishes  are  quite  abundant  in 
some  localities,  and  most  of  them  have  heterocercal 
tails.  Sunderland  in  Massachusetts  is  a  famous  locali- 
ty for  obtaining  fossil  fish  of  this  period.  The  shales 
in  which  they  are  found  contain  considerable  petro- 
leum ;  and  this  petroleum  may  have  been  the  cause 
of  their  death,  and  the  means  of  their  preservation  as 
fossils. 

Fossil  reptiles  have  been  found  in  this  formation  in 
North  Carolina,  Prince  Edward's  Island,  and  Phcenixville, 
Penn.  In  the  Bunter  Sandstein,  or  colored  sandstone  of 
Germany,  and  in  Lancashire  and  Cheshire  in  England, 
many  footprints  of  an  enormous,  frog-like  reptile  have 
been  found,  called  originally  clieirotherium,  or  hand- 
beast  ;  for  the  impression  made  by  the  foot  of  the  animal 
resembled  that  of  a  rude,  human  hand.  One  slab  con- 
taining them  (Fig.  20),  from  the  new  red  sandstone  at 

Fig.  20. 


Cheirotherium  Barthi. 


Jena  in  Germany,  is  now  in  the  Ward  Museum,  Roches- 
ter, N.Y.  The  tracks  of  the  hind-feet  are  about  eight 
inches  long,  and  five  wide;  and  the  fore-feet,  four 
inches  long  and  three  wide.  Remains  of  this  animal 
have  since  been  discovered;  and  it  is  now  known  as 


166  LECTURES  ON  GEOLOGY. 

the  labyrinthodon,  from  tne  labyrinthine  appearance  of 
the  interior  of  the  teeth.  Fig. 
21  represents  the  head  of  one 
found  near  Stuttgart,  Wurtem- 
berg.  The  body  has  not  yet  been 
discovered,  but,  from  the  size  of 
the  head,  is  estimated  at  nine  feet 
in  length.  It  was  covered  with 
scales.  This  reptile  first  made  its 
appearance  in  the  carboniferous 
formation,  but  was  then  smaller. 

Another  remarkable  reptile  of 
this  time,  of  which  but  the  head 
has  been  discovered,  is  the  placodus,  or  plate-tooth,  as  its 
name  signifies.  Its  crushing  teeth  were  like  paving- 
stones.  It  was  discovered  in  the  muschelkalk,  at 
Laineck,  in  Bavaria,  associated  with  multitudes  of  fossil 
shells,  which  have  given  their  name  to  the  strata ;  and 
there  is  little  doubt  that  the  teeth  were  used,  being  well 
adapted  for  that  purpose,  to  crush  the  shells  of  the 
mollusks  on  which  the  reptile  fed.  Of  the  last  tooth,  says 
Owen, lt  It  is,  in  proportion  to  the  entire  skull,  the  largest 
grinding  tooth  in  the  animal  kingdom." 

In  triassic  beds  of  England,  Germany,  and  in  coal- 
beds  in  North  Carolina,  supposed  to  be  of  this  age,  we 
find  the  first  mammals  that  have  yet  been  discovered. 
They  are  all  small  in  size.  From  the  shape  of  their 
teeth,  they  appear  to  have  been  insectivorous,  that  is, 
insect-eating;  and,  according  to  Owen,  they  were  proba- 
bly marsupial,  that  is,  had  a  pouch  for  their  young,  like 
the  opossum.  This  fact  is  one  well  worthy  of  remem- 
brance ;  these  earliest  known  mammals,  from  such  widely- 
separated  localities,  boing  all  referred  to  a  type,  the 


LECTURES  ON  GEOLOGY.  167 

marsupial,  which  is  that  type  of  mammals  most  closely 
allied  to  birds  in  its  organization,  and  belonging  to  the 
lowest  order  of  the  class. 

The  Bunter  Sandstein  is  a  fine-grained,  whitish  sand- 
stone, some  of  it  nearly  as  coarse  as  conglomerate,  and 
used  for  making  millstones.  Occasionally,  beds  of  marl 
are  found  associated  with  it.  It  is  spread  over  a  large 
portion  of  France  and  Germany,  and  in  many  districts 
contains  numerous  remains  of  fossil  plants  and  marine 
shells. 

The  musclielkalk  is  a  compact  limestone  of  a  grayish 
color,  and  abounds  with  the  remains  of  radiates,  shells,' 
and  fishes.  The  ocean  in  which  it  was  deposited 
appears  to  have  been  very  muddy,  and  therefore  un- 
favorable to  the  growth  of  coral.  The  polyps  could  find 
no  solid  foundation  on  which  to  build ;  but,  for  that 
reason,  it  was  eminently  favorable  for  the  growth  of 
crinoids,  in  which  it  abounds.  One  species,  termed  the 
lily  encrinite,  is  composed  of  twenty-six  thousand  sepa- 
rate pieces. 

The  remains  of  fishes  are  most  abundant,  consisting 
mostly  of  teeth  and  scales :  the  teeth,  round  and  flat- 
tened, were  distributed  over  all  parts  of  the  palate,  and 
were  just  suited  to  the  work  of  crushing  shells,  such  as 
abound  in  this  formation,  and  from  which  it  receives  its 
name. 

The  triassic  period  I  regard  as  one  of  the  most  remark- 
able in  the  world's  eventful  history.  Fishes  abound; 
reptiles  are  more  common  and  larger  than  in  any 
previous  time;  birds  are  numerous  and  gigantic;  and 
mammals  appear.  We  may  expect  much  light  to  be 
thrown  upon  the  early  history  of  birds  by  a  more  care- 


168  LECTURES  ON  GEOLOGY. 

ful  study  of  the  footprints  of  tlie  Connecticut  Valley ; 
and  shall  probably  discover  many  linking  forms  be- 
tween birds  and  lizards,  which  seem  to  have  existed  in 
the  greatest  abundance  during  this  time.  I  think  it, 
however,  highly  probable  that  the  beds  of  the  Connecti- 
cut Valley  will  be  found  to  be  much  more  recent  than 
has  been  generally  supposed. 


LECTURE   IV. 


BY  this  time,  there  are  some  explanations  necessary  to 
clear  the  way  that  lies  before  us,  and  to  make  more  dis- 
tinct and  accurate  our  knowledge  of  that  already  gone 
over.  I  have  spoken  of  the  granite  as  the  oldest  rock  of 
all;  but  this,  although  true  in  the  main,  is  not  absolutely 
so.  As  the  interior  of  the  earth  is  cooling  to-day,  so 
granite  down  there  is  forming  to-day,  as  the  rock  formed 
from  that  cooling,  slowly,  crystallizes.  This  is  equalty 
true  of  all  the  geologic  periods ;  and  we  have  therefore 
granites  of  all  ages,  and  frequently  find  veins  of  it  rami- 
fying through  the  more  recent  formations. 

I  have  also  said  that  the  metamorphic  rocks  were  the 
next  formed,  and  that  they  were  laid  down  at  a  time 
when  no  life  existed  on  the  globe.  This  statement,  though 
generally  correct,  requires  to  be  modified.  As  metamor- 
phic rocks  are  those  sedimentary  rocks  which  have  been 
altered  by  heat,  we  have  metamorphic  rocks  of  all  ages,  be- 
cause, in  all  ages,  rocks  have  been  exposed  to  such  heat  as 
would,  when  cool,  cause  their  particles  to  be  re-arranged 
and  crystallized.  In  Canada,  the  rocks  belonging  to  the 
age  of  radiates,  the  oldest  rocks  in  which  the  remains  of 
living  beings  are  found,  are  so  changed  by  metamorphic 
action,  that  it  was  years  before  the  fossils  abounding  iu 

169 


170  LECTURES  ON  GEOLOGY. 

some  of  them  were  discovered.  In  New  England,  we  have 
in  many  places  metamorphosed  Silurian  and  Devonian 
rocks.  The  limestones,  being  melted,  crystallized  on  cool- 
ing, and  produced  marble,  in  which  fossil  forms  are  com- 
pletely obliterated ;  while  the  original  shales  have  hard- 
ened into  slates.  In  Eastern  Pennsylvania  are  metamor- 
phosed coal-measures,  the  coal  in  which  has  been  trans- 
formed by  heat  from  bituminous  to  anthracite  ;  which  is, 
therefore,  metamorphic  coal.  In  other  parts  of  the  world, 
we  find  metamorphosed  strata  up  to  the  more  recent  ter- 
tiaries.  Some  of  the  beds  that  we  thus  find  are  only 
partially  metamorphosed,  and  fossils  can  be  distinguished 
in  them ;  while  in  others,  thoroughly  done,  all  of  life  that 
the  eye  can  trace  is  gone. 

From  what  has  been  said,  some  might  suppose  thnt  all 
the  rocks,  from  the  granite  up,  lay  in  regular  order  one 
upon  another,  like  the  coats  of  an  onion ;  but  this  is  far 
from  being  so.  Let  the  rocks  be  represented  by  the  num- 
bers one,  two,  three,  four,  &c.  We  frequently  find,  in  fact 
invariably  find,  some  of  these  numbers  wanting.  Num- 
ber three  is  found  lying  on  number  one ;  number  two 
being  absent.  Number  nine  is  found  on  number  four; 
all  between  being  absent.  In  other  cases,  formations 
which  are  ten  thousand  feet  thick  in  one  country  are 
reduced  to  a  thickness  of  forty  or  fifty  feet  in  another. 
Thus,  in  Portugal,  the  coal-measures  rest  upon  the  gran- 
ite ;  and  the  Metamorphic,  Silurian,  and  Devonian  are 
wanting.  On  the  shores  of  Lake  Erie,  glacial  beds  rest 
upon  Devonian  rocks ;  and  all  the  formations  lying 
between  the  Devonian  and  the  drift  are  wanting.  In 
Middle  Tennessee,  the  Devonian  formation,  which  in 
New  York  and  Pennsylvania  is  several  thousand  feet 
in  thickness,  is  reduced  to  a  thickness  of  from  thirty  to 


LECTURES  ON  GEOLOGY.  171 

fifty  feet ;  while  all  the  Silurian  rocks  above  the  Trenton 
limestone  are  wanting. 

There  are  three  reasons  that  may  be  given  for  this  con- 
dition of  things.  One  is;  that  those  parts  of  the  earth 
where  particular  beds  are  wanting  were  dry  land  at  the 
time  when  such  beds  were  laid  down  at  the  bottoms  of 
lakes  or  oceans  :  hence  no  sediment  was  deposited  there, 
and  no  beds  were  formed  ;  instead  of  that,  rains  swept 
over  them,  and  carried  off  sediment,  to  make  deposits  in 
other  localities  covered  by  water.  Thus  we  may  sup- 
pose that  those  portions  of  Portugal  where  the  coal- 
measures  rest  on  the  granite  were  mountain-lands  at  the 
time  that  the  Silurian  and  Devonian  beds  of  Great  Britain 
and  the  United  States  were  forming  at  the  sea-bottom. 
After  the  deposition  of  the  Trenton  limestone,  Middle 
Tennessee  was  probably  elevated  above  the  water-level ; 
while,  in  New  York  and  part  of  Canada,  the  Hudson- 
river  group,  the  Niagara  limestone,  and  the  other  upper 
Silurian  beds,  which  are  wanting  in  Tennessee,  were 
being  deposited. 

Or  those  portions  of  the  earth  may  have  been  covered 
with  the  waters  of  a  deep  sea,  far  from  land  and  sedi- 
ment-bearing rivers  :  for,  in  the  depths  of  the  Atlantic 
and  Pacific,  there  cannot  be  much  sedimentary  deposi- 
tion or  deposits  of  animal  forms,  save  those  of  minute 
infusoria;  and  in  future  time,  should  it  become  dryland, 
the  beds  that  represent  this  age  will  be  found  princi* 
pally  where  the  ocean  is  shallow ;  where  shells,  fishes, 
and  corals  abound ;  and  near  to  rivers,  which  are  con- 
stantly sweeping  in  sediment. 

Or,  lastly,  beds  may  have  existed  representing  those 
periods,  and  been  swept  off  by  denudation  since  that 
time.  Thus,  in  Scotland,  Lyell  tells  us  of  a  great  body 


172  LECTURES  ON  GEOLOGY. 

of  sandstone,  from  one  to  tfiree  thousand  foet  in  thick- 
ness, covering  a  large  part  of  Ross-shire,  that  has  been 
removed,  —  swept  off  by  rains,  rivers,  or  currents,  or  all 
combined.  "  Professor  Ramsay,"  he  says,  "  has  pointed 
out  considerable  areas  in  South  Wales  and  some  of  the 
adjacent  counties  of  England,  where  a  series  of  primary 
strata,  not  less  than  eleven  thousand  feet  in  thickness, 
have  been  swept  off."  When  we  think  that  some  rocks 
must  have  been  exposed  to  the  action  of  the  elements 
for  millions  of  years,  the  amount  of  denudation  must 
be  great :  in  fact,  the  thickness  of  any  formation  is  an 
accurate  measure  of  the  denudation  of  the  previously 
existing  rocks  ;  for  the  world  has  been  built  up  as  the 
modern  Egyptians  build  their  cities,  —  the  ruins  of  the 
old  supplying  material  for  the  new. 

Lias.  —  The  name  "  lias  "  is  an  English  one,  and  was 
probably  given  to  the  group  of  rocks  lying  above  the 
trias,  from  the  fact  that  it  consists  of  a  number  of  thin 
layers  of  limestone,  marl,  and  shales;  "lias"  being, 
probably,  a  corruption  of  layers.  Its  thickness  is  from 
five  hundred  to  a  thousand  feet,  and  it  abounds  through- 
out with  many  remarkable  fossils. 

Shakspeare  has  divided  the  life  of  man  into  seven  ages ; 
and,  not  improperly,  the  organic  period  of  the  world's 
history  may  be  divided  into  a  like  number.  The  age  of 
radiates  :  Before  the  first  shell  clothed  the  first  ocean- 
tenant,  in  the  heated  waters  floated  the  radiates,  crawled 
on  the  sea-bottom,  expanded  their  flower-like  cups,  and, 
without  intermission,  silently  built  their  stony  habi- 
tations in  the  shallow  seas.  The  age  of  shells  or  mol- 
lusks :  Then  shells  paved  the  bed  of  the  sea,  and  accu- 
mulated till  islands  of  them  rose  from  its  depths.  The 
age  of  fishes  :  When  bony-plated  fishes  by  myriads  lashed 


LECTURES   ON  GEOLOGY. 


173 


the  waters  of  all  seas,  and  their  accumulated  remains 

helped  to  build  the  foundations  of  continents.     The  age 

of  plants :  When,  wherever  land  was,  or  marsh,  plants 

flourished   abundantly,  and   green   forests  waved   over 

equator  and  poles  alike.     The   age  of  reptiles :  When 

reptiles  crawled  on  the  land,  swam  in  the  water,  dived 

into  its  depths,  and,  on  leathery 

wings  upborne,  tenanted  even  the 

very  air.      The  age  of  mammals 

next:     When    whales    and    seals 

crowded  each  other  in  the  waters ; 

and  beasts,  from  the  mouse  to  the 

mastodon,  roamed  over  the  land. 

Last,  the  age  of  man,  in  whose 

spring-time  we  live. 

During  the  liassic  period,  the 
ocean  especially  seems  to  have 
swarmed  with  reptilian  forms.  One 
of  the  most  remarkable  was  the 
ichthyosaurus,  or  fish-lizard,  as  its 
name  means  (from  the  Greek  ich- 
tliys,  "  a  fish,"  and  sauros,  "  a  liz- 
ard "  ).  Fig.  22  represents  a  fine 
specimen  from  the  lias  near  Glas- 
tonbury  in  England,  and  now  in 
the  British  Museum.  It  was  as 
large  as  a  young  whale  ;  some  of 
the  largest  measuring  from  thirty 
to  forty  feet  in  length.  We  find 
in  it  the  snout  of  a  porpoise  com- 
bined with  the  teeth  of  a  croco- 
dile, the  head  of  a  lizard  with  the  ichthyosaurus 
backbone  of  a  fish  and  the  breastbone  of  an  ornithorhyn* 


174 


LECTURES   ON  GEOLOGY. 


Fig.  23. 


chus  with  the  paddles  of  a  wliale.  The  moutn  was  wide, 
the  jaws  long, -the  teeth  conical,  and  much  like  those  of 
a  crocodile,  but  more  numerous.  In  some  species,  a 
hundred  and  eighty  have  been  counted.  As  they  were 
liable  to  lose  them,  new  ones  were  pushed 'up  from  below 
to  take  their  place. 

The  eye  was  of  enormous  size,  sometimes  larger  than 
a  man's  head.  Fig.  23  represents  a  head  of  the  ichthy- 
osaurus from  Lyrne  Regis,  Eng- 
land, in  which  the  eye  is  seven 
and  a  half  inches  in  diameter ;  it 
was  protected  by  a  series  of  thin, 
bony  plates.  From  its  great  size, 
this  animal  must  have  been  able 
to  descry  his  prey  in  the  twilight 
depths  of  the  ocean  or  in  the  ob- 
scurity of  night;  for  these  monsters 
lived  by  preying,  as  their  remains 
abundantly  testify.  Within  their 
ribs,  where  the  stomach  was  placed, 
have  been  found  masses  of  half- 
digested  bones  and  scales  of  fishes 
that  lived  in  the  same  seas  and  at 
the  same  time  as  the  ichthyosaurus. 
We  can  tell  not  only  the  food  of 
the  animal,  but  the  size  and  shape 
of  the  stomach  and  intestines.  The 
stomach  formed  a  pouch,  or  sac, 
extending  through  nearly  the  en- 
tire cavity  of  the  body.  Bones  of 

^  k   wagggas^  small    ichthyosauri     have      been 

found  within  the  bodies    of  large 

Ichthyosaurus  platyodon.  .         .      , .      .  ,         ,  ,   .     ,        , 

ones,  the  individuals  to  which  they 
belonged  several  feet  in  length. 


LECTURES  ON  GEOLOGY.  175 

It  is  a  singular  fact  that  their  excrement  is  found  in 
great  abundance ;  and,  under  the  name  of  "  coprolites," 
they  are  gathered,  ground  up,  and  used  for  fertilizing 
English  soils.  In  them  are  also  found  in  abundance  the 
teeth  and  bones  of  fishes  which  have  passed  through 
the  bodies  of  these  reptiles  undigested. 

Such  fossils  as  these  are  of  the  greatest  value  to  the 
geologist,  They  enable  him  to  fortify  his  science  so  as  to 
make  it  impregnable  against  the  attacks  of  those  who 
teach  that  the  world  was  made  "just  as  it  is."  I  saw  a 
Cornishman  digging  for  lead  in  Wisconsin,  and  asked 
him  where  he  supposed  the  shells  came  from  that  abound 
in  the  limestone  there. 

"  Why,"  said  he,  "  the  Lord  made  them  when  he  made 
the  rocks."  Some  men  who  are  pretenders  to  science 
have  lent  their  names  to  the  support  of  a  similar  idea. 
They  argue  thus  :  "  There  is  no  reason  to  believe,  as  geol- 
ogists teach,  that  these  buried  trees,  shells,  fishes,  and 
beasts  ever  had  an  actual  existence.  Could  not  the  God 
who  made  the  myriad  trees  that  adorn  the  earth  to-day 
make  the  appearance  of  trees  in  the  rocks  when  the  world 
was  made  ?  Could  not  He  who  made  the  shells  that  span- 
gle our  seacoasts,  and  the  fishes  that  swim  in  the  ocean- 
depths,  supply  the  rocks  with  the  rude  appearances  of 
these  at  the  beginning?  All  things  were  made  by  the 
Omnipotent,  when  out  of  chaos  the  creative  fiat  brought 
a  perfected  world." 

Five  minutes'  examination  of  a  fossil  ichthyosaurus 
should  be  sufficient  to  show  the  absurdity  of  this  con- 
clusion. Look  at  these  teeth,  long  and  sharp,  for  holding 
the  slippery  prey  !  Some,  as  you  see,  are  worn  by  use, 
and  others  broken ;  while  in  this  young  one  they  are  all 
sharp  and  perfect.  Within  its  ribs  is  a  bony  mass.  We 


176  LECTURES  ON  GEOLOGY. 

break  it,  and  there  are  the  glittering  scales  of  the  fishes 
it  fed  upon,  —  the  remains  of  its  last  breakfast ;  while  the 
coDrol  tes  below  bear  the  impression  of  the  internal 
surface  of  the  intestines  in  which  they  once  lay,  and  in 
them  we  rnay  see  the  undigested  scales  and  teeth  of  the 
fishes  and  reptiles  that  it  had  swallowed.  Are  we  to  be 
told  that  this  was  created  "just  as  it  is  "  when  the  world 
was  made  ?  The  man  that  can  believe  that  must  have 
a  larger  swallow  than  the  ichthyosaurus  itself,  and  is 
quite  as  much  of  a  fossil.  He  should  be  ticketed,  and 
laid  away  on  the  shelf  of  some  museum  for  the  considera- 
tion of  the  curious  in  the  year  2000,  when  the  existence 
of  such  beings  may  be  denied. 

"  But  is  it  not  possible  that  these  were  created  just 
so?"  I  answer,  No.  It  is  not  possible  in  the  nature  of 
things.  There  is  nothing  like  it  in  Nature :  she  does  not 
deal  in  shams  and  make-believes.  What  lies  in  stone 
these  fossils  would  be  !  and  for  no  purpose  but  to  puzzle 
and  perplex  poor  mortals.  And  where  could  we  draw  & 
line  between  the  real  and  the  unreal  ?  "  Are  the  Pyramids 
actual  structures  reared  by  man?  or  were  they,  too, 
made  when  the  world  was  made  ?  Here  is  an  Indian 
mound.  On  opening  it,  we  find  arrow-heads  and  spears 
of  flint,  a  hatchet  of  greenstone,  a  pipe,  and  one  of  those 
sugar-loaf-shaped  skulls  that  indicate  the  ancient  mound' 
builders.  We  commence  to  solve  the  problem  lying 
before  us.  Here  is  the  skull  of  what  was  once  a  man  ; 
for  there  is  a  marked  distinction  between  the  shape  of 
the  m:ile  and  female  head.  He  was  evidently  no  great 
reasoner ;  for  the  reflective  portion  of  the  head  is  low, 
and  the  skull  over  that  region  thick.  He  had  some  con- 
structive talent,  as  these  arrow-heads  and  other  imple- 
ments indicate.  He  did  not  know  the  use  of  iron,  evident- 


LECTURES  ON  GEOLOGY.  177 

ly:  he  did  know  the  use  of  tobacco.  Poor  savage  !  As 
we  are  thus  reasoning,  up  comes  our  world-made-as-it-is 
friend.  "  Nonsense  !  "  he  exclaims.  "  The  God  that  made 
the  mighty  mountains  —  could  he  not  make  a  little  mound 
like  this  ?  He  who  made  man  at  the  beginning  could 
surely  make  the  appearance  of  a  skull.  Pie  who  created 
the  millions  of  grassy  spears  at  our  feet,  and  the  tobacco 
of  the  field,  might  surely  make  these  spears,  hatchets, 
and  this  semblance  of  a  pipe.  They  are  merely  types, 
made  at  the  creation,  of  what  was  destined  to  appear  in 
due  time." 

It  is  just  as  reasonable  to  suppose  that  God  made 
tobacco-pipes  that  men  never  saw  or  smoked  as  that 
he  should  have  made  fishes  and  trees  in  the  rocks  that 
never  lived  or  grew.  Admit  such  reasoning,  or  rather 
the  want  of  it,  as  such  talk  indicates,  and  we  should 
be  bounded  by  the  limitation  of  our  senses,  and  become 
the  veriest  infidels  the  world  ever  saw. 

Thirty  species  of  the  ichthyosaurus  are  known.  It 
was  most  abundant  during  the  time  of  the  lias  and 
oolite. 

Another  marine  reptile  of  the  lias  was  the  plesiosaurus 
(near  to  a  lizard),  from  the  Greek  words  plesion,  "  near 
to,"  and  sauros,  "  lizard."  It  was  so  called  because  nearer 
to  a  lizard  in  its  organization  than  the  ichthyosaurus. 

Fig.  24  represents  a  fine  specimen  from  the  lias  at 
Glastonbury,  England.  DolicJwdeirus,  its  specific  name, 
means  "  long-necked."  The  vertebrae  are  not  double 
concave,  as  in  the  ichthyosaurus  and  in  fishes  j  nor  is  it 
concavo-convex,  hollow  on  one  side  and  rounded  on  the 
other,  as  in  crocodiles,  but  nearly  flat :  and  in  this 
respect,  as  well  as  some  others,  it  resembles  the  land- 

saurians.      This  reptile  was  from  eight  to  twenty  feet 
12 


178 


LECTURES   ON   GEOLOGY. 


long.     It  has  the  head  of  a  lizard,  with  more  than  a  hun- 
dred teeth  like  those  of  a  crocodile ;  a  neck  resembling 
Fig.  24.  the  body  of  a  ser- 

pent, having  thirty- 
three  vertebrae; 
while  living  reptiles 
only  have  from 
three  to  eight.  Its 
trunk  and  tail  re- 
semble those  of  a 
quadruped.  The 
tail  was  short,  but 
the  paddles  long. 

In  the  fore  paddle 
of  the  plesiosaurus 
are  all  the  essential 
parts  of  a  human 
arm,  —  the  scapula, 
humerus,  radius, 
and  ulna,  the  bones 
of  the  carpus  and 
metacarpus,  and  the 
phalanges  for  five 
fingers, —  a  proph- 
ecy (was  it  not  ?)  of 
the  wonder-working 
arm  and  hand  of 
man. 

With  a  long, 
arched  neck,  like 


that   of  a 


swan     n 


Plesioeaurus  dolichodeirus. 


of  those  old  oceans  gracefully  paddled  the  plesiosaururf, 


LECTURES  ON  GEOLOGY. 


179 


darting  down  its  small  head,  and  catching  the  finny 
prey  that  constituted  its  food ;  for  within  its  ribs  have 
vbeen  found  the  remains  of  the  fishes  on  which  it  fed. 

The  most  extraordinary  animal  of  this  time,  and  I  had 
almost  said  of  any  time,  was  the  pterodactyle  ("  wing- 
finger"),  from  the  Greek  words  pteron,  "a  wing,"  and 
daktulos,  "  a  finger." 

Fig.  26. 


Pterodactylus  crassirostris. 

Fig.  25  represents  the  most  perfect  skeleton  of  the 
pterodactyle  ever  found.  It  was  discovered  in  the 
lithographic  limestone  at  Solenhofen,  Bavaria,  asso- 
ciated with  the  remains  of  dragon-flies.  Its  specific 
name,  crassirostris,  means  "  thick-beaked." 

Cuvier,  in  his  "  Osteology,"  gives  the  following  descrip- 
tion of  this  bird-like  reptile :  "  You  see  before  you  an 
animal,  which,  in  all  points  of  bony  structure,  from  the 


180  LECTURES  ON  GEOLOGY. 

teeth  to  the  extremity  of  tn*e  nails,  presents  the  well- 
known  saurian  characteristics,  and  of  which  one  cannot 
doubt  that  its  integuments  and  soft  parts,  its  scaly 
armor,  and  its  organs  of  circulation  and  reproduction, 
were  likewise  analogous.  But  it  was  at  the  same  time 
an  animal  provided  with  the  means  of  flying;  and,  when 
stationary,  its  wings  were  probably  folded  back  like 
those  of  a  bird  ;  although,  perhaps,  by  the  claws  attached 
to  its  fingers,  it  might  suspend  itself  from  the  branches 
of  trees.  Its  usual  position,  when  not  in  motion,  would 
be  on  its  hind-feet,  resting  like  a  bird,  and  with  its  neck 
set  up,  and  curved  backwards,  to  prevent  the  weight  of 
the  enormous  head  from  destroying  its  equilibrium. 
The  animal  was,  undoubtedly,  of  the  most  extraordinary 
kind,  and  would  appear,  if  living,  the  strangest  of  all 
creatures." 

Cuvier  was  mistaken  in  supposing  that  it  had  scaly 
armor :  it  was  more  bird-like,  and  hence  stranger  than 
even  he  supposed. 

It  has  four  fingers,  terminated  with  long  hooked  claws, 
of  about  the  length  that  an  animal  of  its  size  might  be 
expected  to  have ;  but  its  fifth  finger,  occupying  the 
place  of  a  little  finger,  is  inordinately  large  and  long. 
From  this  long  finger  a  web  extended  down  the  side  of 
the  animal's  body,  by  means  of  which  it  could  fly.  The 
•form  of  its  neck  and  the  hollowness  of  its  bones  resem- 
ble those  of  birds  ;  its  wings  approach  those  of  the  bat ; 
its  body  and  tail  are  like  those  of  a  mammal ;  while  its 
beak  is  furnished  with  sixty  sharp,  conical  teeth.  Thus 
one  naturalist  considered  it  to  be  a  bird ;  another  a  kind 
of  bat;  and  a  third  regarded  it  as  a  flying  reptile,  wh'ch 
it  is  now  generally  supposed  to  have  been,  yet  having 
a  very  bird-like  organization. 


LECTURES  ON  GEOLOGY.  181 

It  strongly  reminds  one  of  Milton's  description  of  Satan 
making  his  way  from  Pandemonium  to  Paradise  : — 

"  The  Fiend, 

O'er  bog  or  steep,  through  strait,  rough,  dense,  or  rare, 
With  head,  hands,  wings,  or  feet,  pursues  his  way, 
And  swims,  or  sinks,  or  wades,  or  creeps,  or  flies." 

So  the  pterodactyle  waded,  crept,  walked,  swam,  dived, 
and  flew,  equally  at  home  in  water,  in  air,  or  on  laud. 

Being  found  associated  with  insects,  it  has  generally 
been  regarded  as  an  insectivorous  reptile  ;  but  those 
strong  jaws,  furnished  with  long,  strong,  conical  teeth, 
are  no  mere  fly-nippers.  An  animal  furnished  with  such 
powerful  claws  and  teeth  must  have  been  a  rapacious 
monster,  from  which  but  few  animals  could  escape. 
Diving  in  the  water,  it  seized  the  darting  fish ;  pounced 
upon  struggling  reptiles  on  shore  ;  the  labyrinthodons 
with  their  scaly  bodies  no  doubt  falling  at  times  victims 
to  its  terrible  attacks  :  nor  could  birds  fly  more  rapidly 
than  those  powerful  wings  could  follow. 

Professor  Owen  describes  three  large  species  of 
pterodactyle,  measuring  fifteen  feet  from  the  tip  of  one 
wing  to  the  tip  of  the  other.  He  also  says  that  another 
species,  Pterodactyle  Cuvieri,  was  probably  upborne  on 
an  expanse  of  wing  of  not  less  than  eighteen  feet.  Re- 
cently some  fragments  of  pterodactyle  bones  have  been 
discovered  near  Cambridge,  in  England,  which  Dr.  Buck- 
land,  jun.,  considers  must  have  belonged  to  an  individual 
that  measured  twenty-seven  feet.  Thirty-seven  species 
of  pterodactyles  have  been  identified  and  described. 

Stranger  monsters  than  fable  ever  fancied  peopled 
the  young  world  ;  and  stranger,  perhaps,  than  any  yet 
discovered  remain  to  be  found :  we  "lave  but  read  a  few 
torn  leaves  of  a  large  volume. 


182  LECTURES  ON  GEOLOGY. 

Fossil  vegetable  remains  arti  common,  —  such  as  ferns, 
eycads,  and  conifers,  or  cone-bear  rig  plants.  The 
cycads  are  plants  resembling  palms  in  their  outward 
appearance,  and  cone-bearing  trees  in  their  inward 
structure.  From  the  abundance  of  their  leaves  and 
trunks  found  in  a  fossil  state  in  England,  they  must  have 
formed  at  one  time  a  large  part  of  the  vegetation  of 
Great  Britain. 

Insects  are  very  common  in  some  of  the  limestones  of 
this  period :  several  hundred  specimens  have  been  dis- 
covered in  liassic  beds,  which  bear  a  strong  resemblance 
to  living  insects.  One  band  of  limestone  in  this  forma- 
tion, found  in  Gloucestershire,  England,  has  been  called 
insect  limestone,  from  the  abundance  of  their  remains 
found  in  it. 

Mollusks  were  numerous,  and  some  of  them  of  great 
interest.  Figs.  26  and  27  represent  two  common  forms 


Fig.  26.  Fig.  27. 


Ostrea  Marsha.  Gryphea  arcu.ita. 


found  in  the  liassic  beds  of  Europe.  The  tropical  seas 
of  this  time  abounded  with  cephalopoda,  the  highest 
class  of  mollusks.  Among  them  is  the  nautilus,  the 
ammonite,  and  species  resembling  the  cuttle-fish.  The 
modern  cuttle-fish  is  provided  v  ith  an  ink-bag ;  and,  when 


LECTURES   ON  GEOLOGY. 


183 


Fig.  28. 


pursued  by  an  enemy,  it  darkens  the  water  with  the  ink, 
and,  under  the  cloud  thus  formed,  escapes.  Fossil  ink- 
bags  similar  to  these  have  been  found  in  the  lias,  show- 
ing that  this  is  a  very  ancient  contrivance.  The  animal 
has  been  drawn  by  the  fossil  ink  thus  furnished,  which 
is  said  to  equal  India  ink.  Notwithstanding  this  con- 
trivance, coprolites  of  the  ichthyosaurus  have  been 
found  stained  with  their  ink,  showing  that  they  were 
preyed  upon  by  these  merciless  marauders. 

The    belemnite 
(stone-dart),  as 
one  of  these  cut- 
tle-fish is    called, 
from  the  dart-like 
shape  of  its  inter- 
nal bone  (Fig.  28),  is  very  abundant  in  the  liassic  and 
cretaceous  beds.     More  than 
a  hundred  species  have  been 
described. 

The  ammonite  (Fig.  29) 
derives  its  name  from  its  re- 
semblance to  the  horn  of 
Jupiter  Ammon.  They  are 
found  from  the  size  of  a  cent 
to  the  size  of  a  cart-wheel, 
and  are  frequently  called 
snake-stones.  Scott  refers  to 


Belemnite  OwenH. 


Fig.  29. 


in  his 


Ammonite  Humphresiamiu. 


Thus  Whitby's  nuns,  exulting,  told 
How  that,  of  thousand  snakes,  each  one 
Was  changed  into  a  coil  of  stone 

When  holy  Hilda  prayed  : 
Themselves  within  their  sacred  bound 
Their  stony  folds  had  often  found." 


184  LECTURES  ON  GEOLOGY. 

Being  very  abundant  in*the  liassic  beds  at  Whitby, 
in  Yorkshire,  England,  they  are  collected  and  sold  to 
visitors,  who  sometimes  ask  where  their  heads  are.  The 
collectors,  ready  to  oblige  their  customers,  file  one  end 
of  the  shell  into  the  shape  of  a  head ;  and  so  strong  is 
the  resemblance,  that  he  must  be  an  unreasonable  scep- 
tic who  denies  that  they  are  Lady  Hilda's  veritable  con- 
verted snakes. 

The  shell  of  the  ammonite  is  thin,  and  could  not  there- 
fore endure  much  pressure  ;  but  it  is  strengthened  by 
ribs  and  tubercles,  which  add  to  its  beauty  no  less  than 
its  strength.  The  septa,  or  divisions  of  the  shell,  ramify 
into  each  other  at  the  point  of  junction.  "  Nothing  can 
be  more  beautiful,"  observes  Dr.  Buckland,  "  than  the 
sinuous  winding  of  these  sutures  in  many  species  at  their 
union  with  the  exterior  shell,  adorning  it  with  a  suc- 
cession of  most  graceful  forms,  resembling  foliage  or 
elegant  embroidery ;  and,  when  these  thin  septa  are  con- 
verted (as  they  sometimes  are)  into  iron  pyrites,  the 
edges  appear  like  golden  filigree-work,  meandering  amid 
the  pellucid  spar  that  fills  the  chambers  of  the  shell." 
F.  3o  The  nautilus  (Fig.  30)  (from 

the  Greek  naus,"  a  ship  ")  was  an 
allied  form  inhabiting  the  same 
Oceans.  Its  shell  is  generally 
rounder  and  the  whorls  less 
numerous  than  in  the  ammonite. 
After  the  ammonite  perished, 
the  nautilus  still  continued  to 
pseudo-eiegans.  flourish  ;  and,  in  our  present 
tropical  seas,  two  or  three  species  still  exist.  G.  F. 
Ricbardscn  of  England  has  embodied  this  fact  in  beauti- 
ful  verse,  which  I  have  taken  the  liberty  to  change 
slightly :  — 


LECTURES  ON  GEOLOGY.  185 

*  The  nautilus  and  the  ammonite 

Were  launched  in  storm  and  strife ; 
Each  sent  to  float,  in  its  tiny  boat, 
On  the  wide,  wild  sea  of  life. 

And  each  could  swim  on  the  ocean's  brim, 

And  anon  its  sails  could  furl, 
And  sink  to  sleep  in  the  great  sea  deep, 

In  a  palace  all  of  pearl. 

And  theirs  was  a  bliss  more  fair  than  this 
.  That  we  feel  in  our  colder  time ; 
For  they  were  rife  in  a  tropic  life, 
In  a  brighter,  happier  clime. 

They  swam  'mid  isles  whose  summer  smiles 

No  wintry  winds  annoy  ; 
Whose  groves  were  palm,  whose  air  was  balm, 

Where  life  was  only  joy. 

They  roamed  all  day  through  creek  and  bay, 

And  traversed  the  ocean  deep ; 
And  at  night  they  sank  on  a  coral  bank, 

In  its  fairy  bowers  to  sleep. 

And  the  monsters  vast  of  ages  past 

They  beheld  in  their  ocean  caves : 
They  saw  them  ride  in  their  power  and  pride, 

And  sink  in  their  billowy  graves. 

Thus  hand  in  hand,  from  strand  to  strand, 

They  sailed  in  mirth  and  glee,  — 
Those  fairy  shells,  with  their  crystal  cells, 

Twin-daughters  of  the  sea. 

But  they  came  at  last  to  a  sea  long  past ; 

And,  as  they  reached  its  shore, 
On  the  storm-wind's  breath  came  the  blast  of  death, 

And  the  ammonite  lived  no  more. 


186  LECTURES  ON  GEOLOGY. 

And  the  nautilus  now,  in*its  shelly  prow, 

As  o'er  the  deep  it  strays, 
Still  seems  to  seek  in  bay  and  creek 

Its  companion  of  other  days. 

And  thus  do  we,  on  Life's  stormy  sea, 

As  we  roam  from  shore  to  shore, 
Vhile  tempest-tost,  seek  the  loved,  the  lost, 
But  find  them  on  earth  no  more. 

Yet  the  hope  how  sweet !  —  again  to  meet, 

As  we  look  to  a  distant  strand, 
Vhere  heart  meets  heart',  and  no  more  they  part 
Who  meet  in  that  better  land." 

There  is  poetry  in  geology ;  and  I  am  glad  that  some 
one  has  eyes  to  see  it,  and  ability  to  delineate  it.  Ge- 
ology is  not  that  dry,  dusty  science  that  some  suppose, 
but  instinct  with  life  and  beauty  in  every  part;  and 
what  are  thus  naturally  joined  together  neither  lecturer 
nor  writer  should  put  asunder. 

Oolite.  —  The  oolite  derives  its  name  from  small  egg- 
like  bodies,  resembling  the  roe  of  a  fish,  that  are  found 
in  some  of  its  limestones  (oon  is  the  Greek  for"  egg"). 
On  breaking  these  small  round  bodies,  we  find  in  the  inside 
of  them  a  fragment  of  shell  or  a  grain  of  sand ;  and, 
around  this,  limy  matter  has  gathered  into  a  small  ball. 
These  appear  to  have  been  made  very  much  as  a  con- 
fectioner makes  comfits.  The  seeds  that  he  intends  to 
coat  he  places  in  a  pan,  which  is  constantly  moved  back- 
ward and  forward,  so  as  to  keep  the  seeds  continually 
rolling  while  melted  sugar  is  dropping  upon  them.  In 
this  way,  they  become  pretty  evenly  coated  with  the 
sugar ;  and  the  comfits  are  made,  each  enclosing  a  se'ed. 
Nature  made  comfits  on  a  much  grander  scale  :  the  ocean 
was  the  pan,  fragments  of  shells  and  the  grains  of  sand 


LECTURES  ON  GEOLOGY.  187 

were  the  seeds,  the  waves  of  the  constantly-rolling  sea 
supplied  the  motion,  while  the  lime  contained  in  the 
water  coated  them  with  concentric  layers. 

In  England,  these  rocks  cross  the  country  from  York- 
shire in  the  north-east  to  Dorsetshire  in  the  south-west, 
in  a  belt  having  an  average  width  of  about  thirty  miles. 
Along  the  Yorkshire  coast,  they  form  a  large  part  of  the 
sea-wall ;  and  the  fossils  contained  in  them  are  picked  up 
in  great  abundance. 

The  beds  of  the  lias  and  the  oolite  are  found  on  the 
Jura  Mountains  in  the  west  of  Switzerland,  and  together 
are  frequently  termed  Jurassic  beds  ;  and  both  formations 
are  then  included  in  the  Jurassic  formation,  which,  on 
the  Jura  Mountains,  consists  of  beds  of  whitish  or  yellow- 
ish limestone. 

At  Solenhofen,  in  G-ermany,  there  are  quarries  in  the 
oolitic  formation  which  produce  a  fine-grained  lime- 
stone, which  is  used  for  lithographic  purposes.  A  draw- 
ing being  made  upon  the  smoothed  surface  of  the  stone 
with  a  peculiar  kind  of  ink,  impressions  are  taken  from  it 
by  a  printing-press,  just  as  from  a  wood-cut  or  from  type. 
From  these  quarries  have  been  obtained  an  immense  num- 
ber of  fossil  fishes,  crustaceans  resembling  shrimps  and 
lobsters,  echini  or  sea-eggs,  insects,  reptiles,  and  reptile 
birds.  It  has  been  supposed  that  this  limestone  was 
i  deposited  on  a  coast  where  the  water  was  shallow,  and  on 
the  shores  of  which  flying  reptiles  chased  their  prey. 
{  Among  the  animals  found  in  the  lithographic  stone 
at  Solenhofen  are  many  species  of  the  pterodactyle 
and  several  saurians  ;  but  the  most  remarkable  fossil  is 
one  which  has  been  recently  discovered,  and  termed  the 
archeopteryx.  It  was  probably  a  feathered  reptile  j  but 
the  head  of  the  animal  has  not  yet  been  discovered.  Its 


188  LECTURES  ON  GEOLOGY. 

toes  are  all  armed  with  sharp  claws.  Its  tail,  six  inchey 
long,  consists  of  twenty  vertebrae,  with  a  pair  of  feathers 
attached  to  each  vertebra.  It  appears  to  be  one  of  those 
strange  linking  forms  between  one  class  and  another 
such  as  some  of  the  Connecticut-valley  footprints  indi- 
cate, many  of  which  probably  are  yet  to  be  found. 

At  Stonesfield,  in  England,  have  been  found  several 
jaws  and  teeth  of  small  mammals.  They  are  considered 
marsupial  by  Owen,  and  some  of  them  insectivorous. 
They  most  resemble  some  of  the  marsupial  forms  of 
Australia. 

Owen  refers  to  the  interesting  correspondence  be- 
tween the  organic  remains  of  the  oolite  and  the  existing 
forms  of  the  Australian  continent  and  the  surrounding 
seas.  The  cestracion,  or  Port-Jackson  shark,  with  its 
palatal,  crushing  teeth,  has  given  us  the  key  to  the  larger 
cartilaginous  fishes  of  the  oolite,  which 
Figt31v  had  similar  teeth.  A  recent  species  of 

trigonia  has  been  discovered  on  the 
Australian  coast;  and  the  trigonia  (Fig. 
31)  is  found  in  the  lower  oolite,  Wur- 
temberg.  Even  the  vegetation  of  Aus- 
tralia bears  some  relation  to  that  of 
the  oolite,  as  its  araucarise  and  cyca- 
deous  plants  testify. 

There  is  a  remarkable  bed  in  the  Isle  of  Portland, 
England,  known  as  the  Portland  "Dirt  Bed/'  which  is  the 
soil  of  that  ancient  period,  buried  and  hardened,  but  still 
retaining  so  much  of  its  primitive  condition  as  to  be 
readily  recognized.  It  is  about  a  foot  thick,  and  is  made 
up  of  black  loam  mixed  with  the  remains  of  tropical 
plants,  sticks,  seods,  leaves,  mingled  and  compressed 
together.  Partly  sunk  in  this  black  soil,  and  partly 


LECTURES  ON  GEOLOGY.  189 

covered  by  overlying  slate,  are  silicified  trunks  of  large 
coniferous  trees,  some  of  them  more  than  thirty  feet  long, 
and  stumps  also  silicified,  at  nearly  the  same  intervals 
at  which  trees  are  found  growing  in  a  modern  forest,  with 
their  roots  attached  to  the  earth  in  which  they  grew. 
They  are  from  one  to  three  feet  long,  and  are  mostly 
erect. 

The  remains  of  more  than  a  dozen  species  of  small 
mammals  have  been  found  in  this  "  dirt  bed."  They  are 
generally  regarded  as  marsupial. 

Weaiden.  —  In  the  south-eastern  part  of  England,  there 
is  a  series  of  deposits,  principally  of  fresh  water,  some- 
times classed  with  the  oolite,  consisting  of  limestones, 
marls,  sands,  clay,  and  shales.  Occurring  as  they  do 
in  the  wealds,  or  woods,  of  Sussex  and  Kent,  they  are 
known  as  the  Weaiden  Group,  and  abound  with  remains 
of  plants,  insects,  fishes,  and  peculiar  reptiles. 

The  most  remarkable  fossils  of  the  Weaiden  are  frag- 
ments of  reptiles  which  have  been  discovered  dis- 
tributed through  beds  in  Sussex,  Kent,  and  in  the  Isle 
of  Wight.  Dr.  Mantell,  in  examining  various  quarries 
through  these  parts  of  England,  discovered  fragments 
of  bone  which  could  not  be  attributed  to  the  skeleton 
of  any  known  animal.  They  belonged,  as  he  supposed, 
to  a  reptile ;  for  the  bone-cells  in  reptiles'  bones  are  dif- 
ferent in  shape  from  those  in  birds  and  mammals,  so  that 
the  smallest  fragment  can  be  distinguished.  But  the  enor, 
mous  size  of  the  animal  indicated  by  these  bones  seemed 
to  be  too  great  for  belief;  for  who  could  credit  the  ex- 
istence  of  a  reptile  whose  body  was  larger  than  that  of 
an  elephant?  At  length,  one  fragment  after  another 
having  been  discovered,  it  could  be  no  longer  doubted 
that  an  enormou  3  herbivorous  lizard  had  once  existed  ia 


190  LECTURES  ON  GEOLOGY. 

England,  —  so  large,  that  a  'perfect  thigh-bone  has  been 
found  three  feet  eight  inches  in  length ;  while  some  frag- 
ments indicate  that  this  bone  attained  a  length  in  some 
of  nearly  five  feet,  and,  with  the  muscles  and  integuments, 
must  have  formed  a  limb  eight  or  nine  feet  in  circum- 
ference. If  the  leg-bones  were  of  equal  length,  what  a 
colossal  reptile  was  this  !  —  the  top  of  whose  back  a  man 
on  horseback  could  not  have  reached.  Its  teeth  resem- 
ble those  of  a  lizard  found  in  the  "West  Indies,  and  called 
iguana:  hence  this  animal  is  called  iguanadon( pronounced 
igwaunadon),  or  iguana  tooth.  The  teeth  indicate  a  vege- 
table feeder :  hence  it  must  have  had  a  bulky  body.  A 
model  of  one  placed  in  the  Crystal  Palace  at  Sydenham, 
and  there  is  good  reason  to  believe  not  a  whit  larger 
than  some  of  the  originals,  held  twenty-one  gentlemen, 
who  took  dinner  inside ;  Dr.  Owen  sitting  in  its  head  for 
brains. 

A  strange  time  was  this  reptile  age.  The  battle  that 
had  been  waged  in  the  ocean  for  ages  was  now  extended 
to  the  land.  Enormous  lizards  wandered  through  tropi- 
cal woods,  feeding  upon  plants  and  soft-bodied  trees : 
others,  making  up,  in  strength,  agility,  and  ferocity,  what 
they  lacked  in  size,  fed,  in  turn,  upon  them  and  on  each 
other.  Reptiles  in  the  ocean,  swimming  and  diving,  their 
huge  paddles  leaving  a  wake  behind  them  like  a  steam- 
boat ;  others  on  the  shore,  crawling,  or  basking  in  the  sun 
on  the  heated  rocks.  Some  have  naked  skins ;  others 
glitter  with  scaly  coats  of  impenetrable  mail;  while  bony 
fringes  ornament  still  others  in  serrated  rows  along  the 
spine.  Stranger  still,  here  are  reptiles  with  wings  ;  some 
clad  with  feathers,  that  mount  and  riot  in  air.  The 
whole  world  was  giv°n  up  to  cold-blooded  monsters; 
and  for  immense  periods  it  must  have  seemed  as  if 


LECTURES  ON  GEOLOGY.  191 

these  were  the  highest  existences  destined  to  dwell  on 
its  surface. 

The  megalosaurus  (large  lizard)  sometimes  attained 
the  length  of  thirty  feet.  This  reptile  was  carnivorous, 
furnished  with  teeth  admirably  adapted  for  their  office. 
Dr.  Buckland  says  of  them,  "  In  the  structure  of  these 
teeth,  we  find  a  combination  of  mechanical  contrivances 
analogous  to  those  which  are  adopted  in  the  construction 
of  the  knife,  the  sabre,  and  the  saw."  Each  tooth  had  a 
double  serrated  edge  of  enamel ;  so  that  it  cut  "like  the 
two-edged  point  of  a  sabre,  equally  on  each  side."  The 
older  teeth  are  curved  backward  like  a  pruning-knife ; 
and  the  convex  portion  is  thick,  as  the  back  of  a  knife  is 
made  thick  to  increase  its  strength.  These  teeth  are 
sometimes  found  broken,  no  doubt  in  the  terrible  conflicts 
that  took  place  between  it  and  its  scaly  prey  j  and  the 
young  tooth  is  frequently  found  in  the  jaw,  ready  to  take 
the  place  of  the  old  one  when  its  work  is  done.  No  per- 
fect skeleton  of  this  rapacious  monster  has  yet  been  found; 
but,  as  Dr.  Buckland  says,  so  many  perfect  bones  and 
teeth  have  been  discovered,  that  we  are  nearly  as 
well  acquainted  with  it  as  we  should  have  been  if  the 
whole  skeleton  had  been  found.  The  poet  must  have 
had  such  a  reptile  as  this  in  his  mind's  eye  when  he 
wrote,  — 

"  See  !  — late  awaked,  emerging  from  the  woods, 
He  stretches  forth  his  stature  to  the  clouds, 
Writhes  in  the  sun  aloft  his  scaly  height, 
And  strikes  the  distant  hills  with  transient  light. 
Far  round  are  fatal  damps  of  terror  spread : 
The  mighty  fear,  nor  blush  to  own  their  dread. 
Large  is  his  front ;  and,  when  his  burnished  eyes 
Lift  their  broad  lids,  the  morning  seems  to  rise." 


192  LECTURES  ON  GEOLOGY. 

The  hylceosaurus,  or  wood-lizard,  as  its  name  implies, 
was  probably  an  herbivorous  (herb-eating)  reptile,  from 
twenty  to  thirty  feet  in  length.  It  was  furnished  with 
a  crest  along  the  back,  composed  of  bones,  some  of  which 
have  been  found  seventeen  inches  long,  and  five  inches 
broad  at  the  base.  Some  existing  lizards  have  small  car- 
tilaginous or  gristly  fringes  of  a  similar  kind ;  but  these 
lizards  of  the  olden  time  were  as  much  superior  to  living 
ones  in  this  respect  as  they  were  in  size  .and  power. 

I  am  frequently  asked,  How  is  it,  if  the  earth  was  ad- 
vancing during  all  these  geologic  ages,  that  such  in- 
ferior forms  of  life  exist  now,  compared  with  those  of 
the  past?  There  are  no  such  shells  as  the  gigantic  ce- 
phalopods  of  the  Silurian  seas ;  no  such  club-mosses  or 
horse-tails,  no  such  tall  reeds  as  waved  in  the  carbo- 
niferous swamps :  our  largest  living  reptiles  are  dwarfs 
compared  with  those  of  the  oolitic  times.  How  is  this? 
The  answer  is,  That  the  earth  has  been  advancing  .as  an 
abode  of  superior  existences.  The  Silurian  period  was 
one  better  fitted  for  shell-life  than  any  other;  and  hence, 
during  this  period,  shells  attained  their  greatest  size, 
and  were  most  abundant.  The  Devonian  period  was 
one  better  fitted  for  fish-life :  hence  fish  multiplied,  and 
shells  dwindled.  The  reptile  period  was  one  in  which 
the  world  was  better  fitted  as  an  abode  for  reptiles  than 
any  other  life-forms :  hence  their  gigantic  size  and  im- 
mense numbers  during  this  period.  But,  when  the  earth 
became  prepared  for  mammals,  it  was  less  favorable  for 
reptiles  (the  conditions  that  best  suited  them  having 
passed  away),  and  beasts  grew  and  multiplied;  and,  as 
it  becomes  best  fitted  for  man's  abode,  the  beasts  dwin- 
dle, and  man  continually  improves. 

From  the  discoveries  made  in  the  Wealden  beds,  it 


LECTURES  ON  GEOLOGY.  193 

seems  evident  that  a  river  like  the  Mississippi  rolled 
over  a  continent,  a  large  portion  of  which,  probably,  now 
lies  beneath  the  bed  of  the  Atlantic,  sweeping  into  an 
estuary  where  the  south-east  of  England  now  is,  carry- 
ing down  the  spoil  of  the  forest,  and  the  remains  of  the 
various  creatures  that  dwelt  on  its  banks  or  floated  in 
its  waters.  The  sea  has  gathered,  again  and  again, 
islands  and  continents  into  this  their  common  grave ; 
again  and  again  to  rise,  and  be  crowned  with  life  more 
triumphantly  than  before. 


CRETACEOUS  PERIOD. 

Above  the  Wealden  come  the  cretaceous  beds.  Greta 
is  the  Latin  word  for  "chalk ; "  and  this  formation  derives 
its  name  from  the  abundance  of  chalk  found  in  it.  The 
white  chalk-cliffs  of  England  have  been  noted  from  the 
earliest  times.  Like  giants,  they  stand  around  the  coast, 
guardians  of  the  old  land.  They  are  portions  of  a  great 
chalk-bed  extending  over  a  large  part  of  Europe. 

Whence  came  this  soft,  white  rock,  called  chalk,  with 
which  we  are  all  well  acquainted  ?  At  first  sight,  it 
seems  a  difficult  problem  with  which  to  deal.  Geology, 
however,  solves  it.  On  close  examination,  we  find  chalk 
to  be  another  of  those  wonderful  productions  formed  in 
the  great  laboratory  of  life. 

When  writing  on  a  blackboard,  I  have  sometimes 
noticed  a  hard,  offending  particle  that  scratched  the 
board  ;  and,  on  carefully  whittling  with  a  pen-knife,  have 
discovered  a  perfect  shell  that  had  been  enveloped  in 
the  chalk.  Large,  perfect  shells  are  frequently  found, 
Bometimes  spiny  shells;  every  spine  perfectly  preserved 

18 


194  LECTURES  ON  GEOLOGY. 

in  the  soft  mud,  now  chalk,  tliat  surrounds  it.  But  the 
fossils  found  in  chalk  'in  this  way  are  few  in  number 
compared  with  those  that  are  to  be  discovered  in  it. 
Take  a  tooth-brush,  and  brush  into  a  teacup  powder 
from  a  piece  of  chalk ;  wash  it,  pouring  out  the  turbid 
water  until  you  have  the  clean  sediment  at  the  bottom : 
on  examining  this,  you  may  see  with  the  naked  eye 
small  shells,  spines  of  the  echinus,  spiculse,  or  small 
spines  of  sponges,  and  fragments  of  corals.  But  what 
you  can  thus  behold  is  but  a  small  portion  of  what  it 
really  contains.  A  drop  of  the  turbid  water  laid  upon 
glass,  and  evaporated,  leaves  a  white  stain  upon  it.  On 
this  place  a  little  Canada  balsam,  and  heat  over  a  spirit- 
lamp  ;  and  under  the  microscope  you  may  then  behold 
multitudes  of  shells,  and  fragments  of  shells,  and  other 
organic  forms  too  small  to  be  visible  to  the  naked  eye. 
Ehrenberg  calculates  that  in  one  cubic  inch  of  chalk 
there  are  a  million  and  a  half  perfect  fossil  shells.  Little 
think  those  ladies  who  powder  their  faces  with  prepared 
chalk,  that,  if  we  had  microscopic  eyes,  we  should  see 
their  fair  cheeks  looking  like  the  beach  of  a  tropical  sea 
when  the  tide  has  gone  down, —  strewed  all  over  with 
beautiful  shells  and  corals.  But  perhaps  it  is  best  for 
all  parties  that  we  possess  no  such  eyes. 

At  the  bottoms  of  lagoons  and  basins  in  the  West- In- 
dia Islands,  especially  the  Bermudas  and  Bahamas,  a  soft, 
white  mud  is  found,  which  is  produced  by  the  wearing- 
down  of  corals  by  the  waves  washing  over  them,  and 
the  fecal  matter  of  coral-eating  fish.  Darwin  tells  us  of 
fishes  seen  through  the  clear  waters  in  the  Pacific  Ocean 
feeding  in  immense  numbers  on  living  corals.  On  open- 
ing their  bodies,  their  intestines  were  found  full  of  im- 
pure chalk. 


LECTURES  ON  GEOLOGY.  195 

I  have  seen  dried  specimens  of  the  white  mud  ob- 
tained from  the  sea-bottom,  in  the  West  Indies,  that 
could  scarcely  be  distinguished  from  chalk.  Similar 
conditions  to  those  that  now  obtain  in  the  neighborhood 
of  some  of  our  coral  islands  may  have  assisted  in  form- 
ing the  chalk-beds. 

But  how  shall  we  account  for  the  existence  of  flint, 
sometimes  found  in  nodules  in  the  heart  of  the  chalk, 
but  most  frequently  in  layers  between  the  chalk-beds, 
three  or  four  feet  apart? — flint,  so  hard,  often  black,  so 
utterly  different  from  chalk.  When  we  break  flints,  we 
frequently  find  fossils  in  their  interior :  shells,  corals,  and 
echini,  or  sea-eggs,  are  very  common,  turning  out  of 
the  flint,  under  the  hammer,  as  a  kernel  does  out  of  a 
hazel-nut.  Nay,  the  solid  flint  itself,  presenting  no 
appearance  of  organic  forms  to  the  naked  eye,  on  being 
chipped  off  in  transparent  splinters,  and  placed  under 
the  microscope,  frequently  reveals  infusorial  shells  in 
great  numbers.  In  a  sea  swarming  with  life,  abounding 
with  infusoria,  sponges,  corals,  echini,  shells,  and  fishes, 
calcareous  or  limy  mud  settled  to  the  bottom  for  a  vast 
period  ;  and,  as  the  various  forms  successively  dropped 
into  it,  they  were  enveloped  in  this  white  mud,  which 
subsequently  hardened  into  chalk.  In  this  mud  were 
abundance  of  silicious  or  flinty  ^shells,  as  well  as  limy 
ones,  flinty  infusoria,  and  spines  of  sponges  and  silica, 
deposited  by  thermal  springs,  whose  waters  held  it  in 
solution.  These  all  mixed  at  first  with  the  calcareous 
mud  at  the  sea-bottom,  became  separated  in  time,  and 
formed  the  nodules  of  flint,  so  common,  especially  in 
the  upper  chalk.  But  how  was  this  done?  "  Birds  of 
a  feather  flock  together,"  says  the  old  proverb  ;  but, 
what  is  very  singular,  minerals  in  a  fine  state  of  sul> 


196  LECTURES   ON   GEOLOGY. 

division  have  a  similar  tendency.  Felspar  and  quartz, 
ground  to  a  fine  powder  and  mixed  together,  as  in  the 
English  and  French  potteries,  require  to  be  ground 
over  now  and  then  to  prevent  the  separation  of  the 
clay  and  silica.  I  have  noticed,  where  heaps  of  tailings 
are  collected  at  quartz-mills,  in  Colorado,  after  some 
time  the  sand  and  sulphuret  of  iron  form  parallel  bands, 
distinctly  separated,  though  originally  all  mingled  to- 
gether. The  nodules  of  chert  found  in  sub-carbonifer- 
ous limestone,  and  the  kidney-ore  of  iron  found  in  the 
coal-measures,  were  probably  formed  in  a  similar  way. 
Thus  flinty  shells,  sponges  containing  flinty  spiculae,  and 
spiny  echini,  or  sea-urchins,  formed  the  centres  around 
which  the  flinty  particles  gathered  out  of  the  soft,  white 
mud;  and  hence  it  is  that  we  so  frequently  find  them 
in  a  fossil  state  on  breaking  open  the  nodules  of  flint. 

The  seas  were  drained  eventually  as  the  land  at  the 
bottom  was  lifted  up,  and  the  hollows  of  the  ocean  in 
other  places  deepened ;  both  causes  from  an  early  time 
operating  simultaneously,  and  increasing  the  land-surface 
of  the  earth.  Then  rivers  ran  over  the  soft  rock, 
scooping  out  channels  for  themselves ;  the  waves  of  the 
ocean  beat  against  the  elevated  portions  in  their  neigh- 
borhood, and  thus  in  time  were  formed  the  tall  cliffs  of 
chalk  found  on  the  coast  of  Kent  and  Sussex,  and  the  sea- 
beaches  covered  with  flint-pebbles  that  lie  below  them. 

The  chalk  formation  of  Europe  extends  from  the  north 
of  Ireland  to  the  Crimea  in  the  south  of  Russia,  eleven 
hundred  and  forty  miles  in  length ;  and  from  the  south 
of  Sweden  to  Bordeaux  in  France,  eight  hundred  and 
forty  miles  in  breadth.  Formations  older  than  the  chalk 
separate  the  northern  chalk  region  from  a  southern  one, 
which  is  found  in  Spain,  Italy,  Greece,  and  other  coun- 
tries bordering  on  the  Mediterranean. 


LECTURES  ON  GEOLOGY.  197 

In  England,  geologists  find  the  following  beds, — those 
of  the  lower  cretaceous,  sometimes  called  the  "  greensand 
group,"  consisting  of  beds  of  green  sand,  sandstones, 
limestones,  and  clays ;  and  the  upper  cretaceous,  com- 
posed of  gault,  —  a  stiff,  dark-blue  clay,  abounding  in  well- 
preserved  shells  ;  beds  of  greensand,  called  the  "  upper 
greensand  ;"  lower  chalk,  generally  destitute  of  flints  ; 
and  upper  chalk,  abounding  in  flints.  The  average 
thickness  of  the  chalk  in  England  is  estimated  at  a 
thousand  feet. 

In  America,  true  chalk  is  almost  or  entirely  wanting : 
and  yet  the  cretaceous  formation  covers  a  large  portion 
of  the  continent;  following  the  Atlantic  border,  from 
New  York  to  Florida,  along  the  Gulf  of  Mexico  to 
Western  Texas,  and  northward  through  New  Mexico 
and  Colorado,  where  it  reaches  a  height  of  from  six  to 
seven  thousand  feet  on  the  slope  of  the  Rocky  Moun- 
tains, and  from  there  probably  through  to  the  Arctic 
Ocean. 

The  beds  consist  of  layers  of  sand,  frequently  green ; 
shells,  loosely  packed  or  cemented  together ;  clays,  sand- 
stones, and  limestones.  In  New  Jersey,  beds  of  green 
sand  are  very  common  in  this  formation.  It  consists  of 
little  green  grains,  its  color  due  to  the  presence  of  sili- 
cate of  iron,  mixed  with  sand  and  lime,  which  is  spread 
upon  the  lands  to  fertilize  them,  and  is  known  by  the 
name  of  marl.  The  beds  abound  with  shells  having  a 
great  resemblance  to  those  found  in  the  chalk  of  Europe. 

In  Western  Texas,  beds  of  cream-colored  limestone 
are  found,  which  is  called  by  the  people  there  chimney- 
rock  ;  for  they  build  their  chimneys  of  it.  It  is  an  excellent 
building-material;  for,  when  first  taken  from  the  quarry, 
it  is  soft  enough  to  hew  with  an  axe,  and  smoothe  with  a 


198  LECTURES  ON  GEOLOGY. 

carpenter's  plane,  and  hardens  by  exposure  to  the  air. 
The  time  will  come  when  beautiful  cities  will  be  built 
of  it.  Beneath  this  are  softer  beds,  nearly  as  white  as 
chalk,  containing  fossils  in  great  abundance ;  and,  where 
the  streams  have  eroded  them,  the  traveller  can  walk 
over  what  appears  like  the  beach  of  an  ancient  ocean, 
strewn  with  shells,  corals,  and  fish  bones  and  teeth. 
On  the  Clear  Fork  of  Trinity  Eiver,  I  have  seen  a 
large  extent  of  surface  covered  with  hard,  flinty  shells 
(gryphcea),  lying  so  close  together  that  grass  could  not 
grow  between  them.  Asking  a  farmer  in  the  vicinity 
where  the  shells  came  from,  his  answer  was,  that  he  sup- 
posed the  Indians  were  fond  of  them,  and  brought  them 
from  the  Gulf,  which  is  not  less  than  three  hundred 
miles  distant.  Little  did  he  dream  that  that  spot  was 
once  the  bed  of  an  ocean  in  which  those  shells  flourished 
as  oysters  do  on  our  coasts  to-day ;  that  they  became 
enveloped  in  mud,  which  hardened  in  time  into  rock, 
the  silicious  particles  filling  the  pores  of  the  shell,  and 
making  it  of  flinty  hardness ;  that  the  ocean-bed  was 
raised,  the  water  drained  off,  and  the  torrents  of  ages, 
sweeping  off  the  soft  limestone,  left  the  hard  shells  to 
tell  the  wonderful  story. 

In  Colorado,  the  cretaceous  formation  consists  of  im- 
mense beds  of  limestone,  and  thinner  beds  of  sandstone, 
both  abounding  with  fossil  remains.  The  various  branches 
of  the  Platte  and  Arkansas  have  worn  out  numerous  and 
frequently  wide  valleys  .in  them. 

In  the  cretaceous  beds,  we  have  the  first  of  true 
palms,  and  of  trees  possessing  a  true  bark.  More  than 
a  hundred  species  of  the  last  have  been  collected. 
Among  them  are  the  oak,  beech,  poplar,  willow,  alder, 
buttoj  wood,  dogwood,  tulip-tree,  and  sassafras.  These 


LECTURES   ON  GEOLOGY. 


199 


have  been  found  in  New  Jersey,  Alabama,  Nebraska, 
Kan&as,  New  Mexico,  and  Vancouver's  Island.  In  Eng- 
land, a  few  seaweeds  and  cone-bearing  trees  have  been 
found  ;  but  few  remains  of  land-plants  have  been  dis- 
covered. In  Colorado,  there  are  coal-beds  of  this  age ; 
so  that,  in  some  places,  swampy  forests  must  have  ex- 
isted, as  in  the  time  of  the  coal-measures.  Large  beds 
of  lignite  are  found  on  the  continent  of  Europe  in  strata 
of  this  age. 

Radiate  animals  are  very  abundant  in  the  cretaceous 
beds ;  the  most  common  being  the  echinus,  which  is 
found  abundantly  in  the  English  flints,  and  still  more 
abundantly  in  some  of  the  limestones  in  Texas.  I  have 
seen  fossil  echinites  in  some  streams  there  nearly  as 
abundant  as  pebbles  are  in  others.  One  species  is 
called  by  the  people  there  "the  lone  star  of  Texas,"  from 
the  star-like  markings  on  its  upper  surface.  Fig.  32 


Fig.  32. 


Fig.  33. 


Micraster  cor-anguinum. 


Ananchytes  ovata. 


represents  one  species  from  the  chalk  of  England ;  and 
Fig.  83,  another  from  the  chalk  of  France.  Micraster 
means  "little  star;  "and  cor-anguinum,  "snake-heart;"  its 
shape  and  its  markings  suggesting  the  name.  Ana.iv 
dnjtes  means  not  pressed;  "  and  ovata,  "  egg-shaped; '' 


200 


LECTURES   ON   GEOLOGY. 


Fig.  35. 


the  shape  again  suggesting  flie  name.  Corals,  sponges, 
star-fishes,  and  other  zoophytes,  are  frequently  found 
in  flint-nodules ;  the  sponges  often  giving  shape  to  the 
flints,  their  pores  having  been  filled  by  silicious  matter. 
Fig.  34.  Fig.  34  represents  a  pear- 

shaped  sponge  from  Eng- 
land; and  Fig.  35,  another 
cretaceous  sponge,  some- 
what like  a  funnel:  they 
are  of  solid  flint. 

Shells  of  many  kinds 
are  common  in  cretaceous 
rocks.  More  than  a  thou- 
sand species  are  known, 
Some  grew  to  an  immense  size,  and 
were  of  great  beauty.  Cephalopods, 

Biphoniapyriformis.  guch    ^    ftlQ    ammonjte    and    lruiti]us? 

abound.  Several  cephalopods  existed  which  are  appar- 
ently modified  forms  of  the  ammonite.  The  baculite, 
from  the  Latin  baculum,  "  a  walking-stick,"  resembles 
a  straight  ammonite.  The  turrilite  (Fig.  36),  from 


Fig.  36. 


Fig.  37. 


Turrilite  costatus. 


Scaphites  Ivanii. 

the  Latin  turris,  "  a  tower,"  may  be  described  as  an 
ammonite  twisted  in  a  tower-like  form.  The  scapliite 
(Fig.  37),  from  the  Litin  scapha,  "a  skiff/'  find  the 
anc'/loceras,  "curve  horn"  (Fig.  38),  are  ammonites  with 
the  shell  partly  uncoiled.  The  crioceras,  "ram's  horn" 


LECTURES  ON  GEOLOGY.  201 

(Fig.  39),  is  an  ammonite,  with  a  space  between  the 
whorls.     I  have  seen  the  children  in  Texas  playing  with 


Fig.  38. 


Ancyloceras  gigas. 

large    ammonites,  which   they    trundled   to    see  which 

could  make  them  go  farthest,  just  as  boys  do  with  hoops. 

The   baculite    is  very  abundant   in  Fig.  39. 

the    cretaceous    beds    of  Colorado, 

where   it  is  styled  a  fossil-fish.     It 

is   sometimes  found  several  feet  in 

length.       The    cretaceous    beaches 

must   have    presented    a   handsome 

appearance      strewed     with     these 

enormous      and      beautiful      shells. 

The  ocean  itself  could  not  probably 

be  better  described  than  in  the  words  of  Percival :  — 

"  Deep  in  the  waves  is  a  coral-grove, 
Where  the  purple  mullet  and  gold-fish  rove ; 
Where  the  sea-flower  spreads  its  leaves  of  blue, 
That  never  are  wet  with  the  falling  dew, 
But  in  bright  and  changeful  beauty  shine 
Far  <J~  awn  in  the  green  and  glassy  brine. 


202  LECTURES  ON  GEOLOGY. 

The  floor  is  of  sand,  like  the  mountain-drift ; 
And  the  pearl-shells  spangle  the  flinty  snow : 
From  coral-rocks  the  sea-plants  lift 
Their  boughs  where  the  tides  and  billows  flow. 
The  water  is  calm  and  still  below, 
For  the  winds  and  the  waves  are  absent  there ; 
And  the  sands  are  bright  as  the  stars  that  glow 
In  the  motionless  fields  of  the  upper  air. 
There,  with  its  waving  blade  of  green, 
The  sea-flag  waves  through  the  silent  water; 
And  the  crimson  leaf  of  the  dulse  is  seen 
To  blush  like  a  banner  bathed  in  slaughter: 
There,  with  a  light  and  easy  motion, 
Thefan-^coral  sweeps  through  the  clear,  deep  sea; 
And  the  yellow  and  scarlet  jtufts  of  ocean 
Are  bending  like  corn  on  the  upland  lea ; 
And  life,  in  rare  and  beautiful  forms, 
Is  sporting  amid  those  bowers  of  stone ; 
While  the  wrathful  Spirit  of  storms 
Has  made  the  top  of  the  waves  his  own." 

Speaking  of  some  of  the  French  cretaceous  beds,D'Or. 
bigny  says,  "  It  seems  as  if  the  sea  had  retired  in  order  to 
show  us,  still  intact,  the  submarine  fauna  of  this  period, 
such  as  it  was  when  in  life.  There  are  here  groups  of 
polyps,  echinoderms,  and  mollusks,  which  lived  in  union 
in  animal  colonies  analogous  to  those  which  still  exist  in 
the  coral  reefs  of  the  Antilles  and  Oceanica.  In  order 
that  these  groups  should  be  preserved,  it  was  necessary 
that  they  should  be  'covered  at  once,  and  suddenly, 
by  the  sediment  which  is  now,  after  being  destroyed  by 
the  action  of  the  atmosphere,  revealing  to  us  in  their 
most  secret  details  the  nature  of  the  ages  which  have 
passed." 

The  waters  abounded  with  fish,  some  of  which  have 
been  found  in  the  chalk  absolutely  round  and  perfect  as 


LECTURES  ON  GEOLOGY.  203 

when  they  were  alive.  Some  rocks  are  covered  with 
the  impressions  of  their  scales,  and  others  are  largely 
made  up  of  their  teeth  and  bones.  Near  the  Green- 
horn River,  one  of  the  branches  of  the  Arkansas,  the 
sandstones,  which  alternate  with  limestones,  and  form 
terraces  along  the  river-valleys  in  consequence  of  their 
hardness,  are  in  some  places  literally  paved  with  teeth ; 
the  most  common  belonging  to  species  of  the  genera 
ptycliodus,  meaning  "folded  tooth,"  and  acrodus,  meaning 
"  hump  tooth,"  so  called  from  the  shape  of  the  teeth.  The 
waters  abounded  in  sharks,  though  they  do  not  appear 
to  have  attained  the  size  that  they  did  subsequently. 
We  do  not  often  find  their  bones,  for  they  had  carti- 
laginous or  gristly  skeletons ;  but  portions  of  the  sha- 
green or  pimpled  skin  have  been  found  in  the  chalk 
of  England. 

Several  specimens  of  the  macropoma,  a  fish  from  one 
to  two  feet  in  length,  have  been  found  in  the  chalk 
nearly  perfect.  Even  the  membranes  of  the  stomach  are 
preserved,  and  separate  in  flakes  ;  and  the  ramification 
of  the  minute  vessels  is  visible  with  a  high  magnifying 
power.  With  the  remains  of  the  macropoma  have  been 
found  coprolites  containing  scales  and  bones  of  fishes, 
affording  evidence  of  its  predaceous  character. 

Of  reptiles,  the  cretaceous  formation  in  England  has 
yielded  twenty-four  species.  The  ichthyosaurus  and  ple- 
siosaurus  occur,  though  rarely ;  and  various  fragments 
of  the  pterodactyle  have  been  found.  These  three  forms 
seem,  however,  to  have  died  out  with  the  cretaceous 
period ;  at  least,  no  fragments  have  yet  been  found  in 
the  younger  groups  of  rocks. 

In  this  formation,  the  mosasaurus,  or  great  rept.le  of 
the  Meuse,  a  river  in  Holland,  makes  its  appearance. 


204  LECTURES  ON  GEOLOGY. 

Its    head    (Fig.  40)    was    discovered    in  a  quarry  near 
Maestricht  on  the  Meuse,  by  Dr.  Hoffman,  from  whom  it 

Fig.  40. 


Jrloeasanrus  Hoffmann!. 


receives  its  specific  name;  and  at  first  puzzled  naturalists 
considerably.  Some  thought  it  a  whale ;  and  others,  a 
crocodile.  It  is,  however,  a  marine  lizard,  allied  to  the 
monitor  of  the  Nile.  Its  head  is  five  feet  long,  and  its 
whole  length  is  estimated  at  twenty-four  feet.  The 
teeth  are  directed  backward,  like  the  barb  of  a  hook  ; 
and  there  is  no  doubt  that  it  was  a  voracious  monster. 

Marine  turtles  were  abundant;  but  the  absence  of  all 
mammals  is  remarkable.  As  they  exis'ted  previous  to 
this,  there  is  no  doubt  that  they  existed  during  this 
time ;  and,  when  the  cretaceous  beds  of  America  shall 
have  been  examined  as  thoroughly  as  those  of  England 
have  been,  I  have  no  doubt  that  this  missing  page  in  the 
volume  will  be  found. 

In  the  marl-pits  of  New  Jersey,  along  with  remains 


LECTURES  ON  GEOLOGY.  205 

of  the  saw-fish  and  sword-fish,  have  been  fcund  those  of 
huge  crocodiles  and  lizards.  A  thigh-bone  of  one  her- 
bivorous reptile,  discovered  near  Haddonfield,  measures 
nearly  four  feet  in  length.  Another,  a  carnivorous  rep- 
tile, supposed  to  have  been  about  eighteen  feet  in  length, 
was  furnished  with  sharp,  serrated,  knife-like  teeth,  and 
had  hind-legs  nearly  seven  feet  long,  while  its  fore-legs 
were  riot  more  than  one-third  as  long.  This  reptile 
must  have  widely  differed  from  any  of  its  modern  rela- 
tions, leaping  with  agility  upon  its  prey.  We  have  seen 
out  a  few  of  the  grand  hosts  that  have  tenanted  earth, 
sea,  arid  air  in  the  past  ages. 

Three  species  of  birds  have  been  discovered  in  this 
formation.  One  found  in  the  chalk  in  Kent,  England, 
resembles  the  albatross;  another,  found  in  Switzerland, 
is  not  unlike  a  swallow :  and  a  third,  found  in  the  Cam- 
bridge greensand,  is  a  bird  about  the  size  of  a  woodcock. 

In  Europe  and  the  eastern  part  of  this  continent  the 
difference  between  the  life-forms  of  the  cretaceous  and 
tertiary  periods  is  so  great,  that  it  has  been  said  that  no 
single  species  passes  from  one  to  the  other.  But  along 
the  base  of  the  Rocky  Mountains,  and  between  the 
ranges,  many  forms  are  common  to  both  ;  so  that  it  is 
difficult  to  distinguish  some  of  the  bordering  groups  of 
rocks. 

During  the  cretaceous  period,  the  sea  covered  a  large 
portion  of  the  North-American  continent.  Commencing 
at  New  Jersey,  the  ocean  occupied  a  strip  of  varied 
width  from  there  westward,  along  the  coast  to  Texas, 
including  the  whole  of  Florida;  extended  up  the  Missis- 
sippi to  the  mouth  of  the  Ohio,  and  in  a  wide  belt  vrom 
Texas,  in  a  north-western  direction,  in  a  line  with  tho 
Rocky-Mountain  range,  probably  to  the  Arctic  Ocean. 


206  LECTURES  ON  GEOLOGY. 

The  ocean  laved  both  sid^fe  of  the  Sierra  Madre,  or  main 
chain  of  the  Kocky  Mountains,  the  range  being  several 
miles  narrower  than  at  present ;  for  we  find  rocks  formed 
during  that  period  occupying  summits  two  and  three 
thousand  feet  above  the  level  of  the  plain,  and  seven  or 
eight  thousand  above  the  sea-level.  The  Colorado  Parks 
seem  to  have  been  inland  seas,  probably  communicating, 
by  what  are  now  passes  over  the  range,  with  the  ex- 
terior ocean. 


TERTIARY    PERIOD. 

A  GE  OF  MA  MM  A  LS. 

In  the  infancy  of  geology,  all  the  rocks  were  simply 
divided  into  primary,  secondary,  and  tertiary,  or  first, 
second,  and  third  ;  but  as  the  science  advanced,  and  the 
earth's  crust  became  better  known,  many  other  groups 
of  rocks  were  found,  and  other  terms  became  necessary. 
But,  though  the  terms  "  primary  "  and  "  secondary  "  are 
seldom  used  by  geologists  now,  "  tertiary  "  has  been  re- 
tained, and  is  applied  to  those  rocks  which  lie  between 
the  cretaceous  formation  and  the  drift. 

The  tertiary  period  has  been  divided  by  Lyell  into 
three,  —  the  eocene,  miocene,  and  pliocene.  Eocene  is 
derived  from  the  Greek  eos,  "  dawn,"  and  TcainoSj  "  re- 
cent," and  signifies  the  dawn  of  the  recent;  for,  at  the 
time  the  name  was  given,  about  six  per  cent  of  the  shells 
found  in  the  eocene  beds  were  believed  to  be  identical 
with  living  species.  Although  we  now  know  that  this 
is  not  the  case,  the  name  is  still  appropriate :  for  the 
outlines  of  land  and  water,  and  the  forms  of  life,  begin 
to  resemble  those  now  existing;  and  we  nray  in  them 


LECTURES  ON  GEOLOGT.  207 

see  the  prophecy  of  the  present,  as  the  first  beams  of 
morning  herald  the  coming  day.  Miocene  is  from 
meion,  "  less/'  and  Jcainos,  "  recent ;  "  and  pliocene  from 
pleion,  "more/'  and  kainos,  "recent;"  the  pliocene 
being  more  recent  than  the  rniocene,  and  the  miocene 
less  recent  than  the  pliocene. 

The  tertiary  period  has  been  called  the  age  of  mam- 
mals. 

Mammals  are  those  animals  that  suckle  their  young. 
They  made  their  appearance,  as  I  have  observed,  before 
the  tertiary  period  ;  but  it  was  then  they  attained  their 
largest  size,  and  flourished  in  greatest  abundance.  The 
class  Mammalia  has  been  divided  by  geologists  into  vari- 
ous orders  ;  those  mammals  being  grouped  together  that 
have  the  greatest  resemblance  to  each  other.  The  most 
common  arrangement  makes  twelve  of  these  orders :  — 

First,  Bimana,  or  two-handed  mammals.  The  only 
animal  belonging  to  this  order  is  man. 

Second,  Quadrumana,  or  four-handed  mammals.  In 
this  order,  all  apes,  monkeys,  and  lemurs  are  placed. 
All  the  four  limbs  are  used  for  grasping.  They  resem- 
ble man  more  nearly  than  any  other  animals. 

Third,  Cheiroptera,  or  hand-winged  mammals.  This 
includes  bats,  whose  forward  limbs  are  wing-like,  en- 
abling them  to  fly  like  birds. 

Fourth,  Insectivora,  or  insect- devourers.  This  in- 
cludes shrews,  moles,  and  hedgehogs,  whose  teeth  are 
so  arranged  as  to  enable  them  most  readily  to  crush  the 
hard  skins  or  shelly  coverings  of  the  insects  that  con- 
stitute their  food. 

Fifth,  Carnivora,  or  flesh-eaters.  This  is  a  large  group, 
containing  all  animals  of  the  cat  and  dog  kind,  as  well 
as  weasels,  bears,  and  other  flesh-eating  mammals.  In 


208  LECTURES  ON  GEOLOGY. 

them,  sharp  teeth  pass  eacfi  other  like  the  blades  of  a 
pair  of  scissors;  and  thus  the  flesh  on  which  they  feed  is 
easily  divided. 

Sixth,  Cetacea,  or  whale-like  mammals.  These  are 
fish-like  in  their  appearance,  and  adapted  for  a  life  in 
the  water.  This  order  includes  the  whale,  the  grampus, 
the  porpoise,  and  some  others.  It  includes  the  largest 
mammals,  and  indeed  the  largest  animals  that  exist. 

Seventh,  Bodentia,  or  gnawing  mammals,  such  as 
rats,  hares,  beavers,  &c.  The  animals  of  this  order  are 
generally  of  small  size,  but  are  very  numerous.  They 
have  four  front  teeth,  or  incisors,  that  are  very  sharp,  by 
which  they  readily  gnaw  nuts,  roots,  and  even  large 
trees. 

Eighth,  Edentata,  or  toothless  mammals.  All  the  ani- 
mals belonging  to  this  order  are  not,  however,  literally 
toothless,  though  some  are  ;  but  all  are  destitute  of 
front  teeth.  In  this  order  are  placed  sloths,  ant-eaters, 
and  armadilloes. 

Ninth,  Pacliydermata,  thick-skinned  mammals.  The* 
elephant,  the  rhinoceros,  the  horse,  and  the  hog  belong 
to  this  order.  Most  of  the  animals  placed  in  this  order 
have  thick  and  naked  skins.  The  largest  land-mammals 
belong  to  this  order. 

Tenth,  Ruminantia,  the  cud-chewers.  All  animals 
that  chew  their  cud  belong  to  this  class,  such  as  the 
ox,  camel,  sheep,  and  deer.  This  order  contains  the 
greatest  number  of  animals  useful  to  man. 

Eleventh,  Marsupialia,  the  pouched  mammals.  This 
includes  those  animals  which  have  a  pouch  for  their 
young,  into  which  they  are  placed,  and  where  they  are 
cared  for  till  they  are  strong  enough  to  shift  for  them- 
selves. The  opossum  and  the  kangaroo  are  of  this  kind. 


LECTURES  ON  GEOLOGY.  209 

Twelfth,  Monotremata.  Mammals  with  one  excretory 
orifice,  like  a  bird.  This  includes  the  ornithorhynchus 
and  some  other  singular  animals  of  New  Holland. 

These  orders  are  again  divided  into  families,  these 
into  genera,  and  the  genera  are  lastly  divided  into  spe- 
cies. Thus  the  wolf,  the  fox,  and  the  jackal  belong  to 
the  genus  Canis,  which  is  the  Latin  for  "  dog :  "  but  the 
dog,  as  a  species,  is  known  as  Canis  familiaris,  or  the 
common  dog ;  the  wolf,  as  Canis  lupus ;  and  the  jackal, 
as  Canis  aureus.  The  cat,  the  lion,  the  tiger,  and  the 
leopard  belong  to  one  genus,  — fells,  or  "  cat."  The 
cat,  is  Fdis  catus  ;  the  lion,  Felis  leo  ;  the  tiger,  Felis  ti- 
gris;  and  the  leopard,  Felis  leopardus.  In  this  way,  the 
scientific  names  for  all  animals  are  formed  ;  the  first  word 
expressing  the  genus,  and  the  last  identifying  the  species. 

When  the  differences  between  animals  are  slight,  as 
between- the  cart-horse  and  the  race-horse,  the  animals 
possessing  them  are  said  to  be  of  different  varieties  j 
when  they  are  greater,  as  between  the  horse  and  the 
ass,  they  are  of  different  species.  There  is  little  doubt 
that  varieties  are  undeveloped  species,  and  species 
undeveloped  genera;  all  lines  of  distinction  drawn  be- 
tween them  being  merely  artificial. 

It  is  probable  that  animals  belonging  to  all  these  or- 
ders, except  the  first,  existed  during  the  eocene  period  ; 
though  some  of  them  were  much  better  represented 
than  others. 

Under  the  city  of  London,  and  in  the  vale  of  the 
Thames  generally,  lies  a  bed  of  clay,  known  by  the  name 
of  "  London  clay,"  which  varies  in  thickness  from  two 
hundred  to  six  hundred  feet.  On  boring  for  water  in 
the  neighborhood  of  London,  the  workmen,  on  passing 
through  this  clay  to  the  underlying  chalk,  obtain  a 
u 


210  LECTURES  ON  GEOLOGY. 

copious  supply  often  rising  to  the  surface.  At  the  Isle 
of  Shepj  y,  at  the  mouth  of  the  Thames,  which  is  en- 
tirely  composed  of  London  clay,  it  is  exposed  in  cliffs, 
some  of  which  are  two  hundred  feet  high,  to  the  action 
of  the  waves  ;  so  that  the  fossils  which  are  contained 
in  it  are  washed  out  in  great  abundance.  Mr.  Bower- 
bank  collected  here  twenty-five  thousand  specimens  of 
fossil  fruits  alone,  belonging  to  six  or  seven  hundred 
different  species.  None  of  them  are  now  living;  but 
they  resemble  tropical  fruits,  such  as  the  date,  cocoa- 
nut,  areca,  custard-apple,  gourd,  melon,  coffee,  scarlet- 
bean,  pepper,  and  cotton-plant,  and  therefore  indicate 
a  climate  such  as  now  exists  in  Ceylon  and  the  West- 
India  Islands.  Forests  of  spices  grew,  and  aromatic 
shrubs  gave  their  odor  to  the  morning  breeze ;  but 
we  look  in  vain  for  beings  sufficiently  advanced  to  en- 
joy them.  How  few  there  are,  even  now,  that  fully 
enjoy  what  Nature  bestows  with  so  lavish  a  hand  !  Many 
species  of  shells  and  fish,  fifty  species  of  which  have 
been  described  by  Agassiz,  indicate,  in  like  manner,  a 
warm  climate. 

Many  extinct  species  of  crabs  and  lobsters  have  been 
found  in  the  London  clay,  also  the  remains  of  crocodiles, 
a  serpent  twenty  feet  long,  a  small  vulture,  a  kind  of 
king-fisher,  a  heron,  a  species  of  sea-gull,  an  opossum, 
and  a  bat. 

That  portion  of  England  where  the  London  clay  is 
found  which  is  called  the  "  London  basin "  appears  at 
that  time  to  have  been  a  gulf,  into  which  fruits,  seeds, 
and  wood  were  probably  drifted  by  currents ;  and,  as 
Mantell  says,  "  the  existence  of  a  group  of  spice-islands 
at  no  great  distance  seems  necessary  to  account  for  so 
vast  an  accumulation  of  vegetable  productions." 


LECTURES  ON  GEOLOGY.  211 

In  France  is  a  Paris  basin,  corresponding  in  some  re- 
spects with  the  London  basin,  though  the  beds  are  more 
numerous,  and  composed  generally  of  different  material. 
They  consist  principally  of  sands,  marls,  limestones,  and 
gypsum,  or  plaster.  At  Montmartre,  close  to  Paris, 
quarries  have  been  opened,  and  gypsum  taken  out  for 
the  manufacture  of  plaster-of-Paris.  As  the  workmen 
dug  out  the  plaster,  they  discovered  bones  in  it,  but 
supposed  them  to  be  the  bones  of  existing  animals,  such 
as  dogs,  horses,  and  sheep  ;  but  the  attention  of  Cuvier, 
the  great  French  naturalist,  being  directed  to  them,  his 
knowledge  of  comparative  anatomy  enabled  him  to  see 
that  these  bones  were  different  from  all  that  he  had 
previously  observed.  He  went  to  the  quarries,  stimu- 
lated the  workmen  by  presents,  and  secured  all  the  bones 
that  they  could  obtain.  These  be  collected  into  a  room, 
and  then  commenced  the  work  of  reconstructing  the 
animals  to  which  they  had  belonged.  He  says,  "  I  at 
length  found  myself  as  if  placed  in  a  charnel-house,  sur- 
rounded by  mutilated  fragments  of  many  hundreds  of 
skeletons  of  more  than  twenty  kinds  of  animals,  piled 
confusedly  around  me.  The  task  assigned  me  was  to 
restore  them  all  to  their  original  position.  At  the  voice 
of  comparative  anatomy,  every  bone,  and  fragment  of  a 
bone,  resumed  its  place.  I  cannot  find  words  to  express 
the  pleasure  I  experienced  in  seeing,  as  I  discovered 
one  character,  how  all  the  consequences  that  I  predicted 
from  it  were  successively  confirmed.  The  feet  were  found 
in  accordance  with  the  characters  announced  by  the 
teeth ;  the  teeth,  in  harmony  with  those  inaicated  be- 
forehand by  the  feet:  the  bones  of  the  thighs  and  legs, 
and  every  connecting  part  of  the  extremities,  were  found 
set  together  precisely  as  I  had  arranged  them  before 


212  LECTURES  ON  GEOLOGY. 

my  conjectures  'were  verified  by  the  discovery  of  tho 
parts  entire." 

Professor  Aneted,  using  the  language  of  Cuvier  as 
far  as  possible,  shows  us  how  such  re-creations  are  pos- 
sible :  — 

"  Thus,  if  the  stomach  of  an  animal  is  so  organized  as 
only  to  digest  fresh  animal  food,  its  jaws  must  also  be 
so  contrived  as  to  devour  such  prey,  its  claws  to  seize 
and  tear  it,  its  teeth  to  cut  and  divide  it,  the  whole 
structure  of  its  locomotive  organs  to  pursue  and  obtain 
it,  its  organs  of  sense  to  perceive  it  from  afar :  and 
Nature  must  even  have  placed  in  its  brain  the  necessary 
instinct  to  enable  it  to  conceal  itself,  and  to  bring  its 
victim  within  its  toils ; "  and  this  would  give  a  certain 
shape  to  the  skull,  which  the  comparative  anatomist 
could  recognize. 

"  That  the  jaw  may  be  enabled  to  seize  the  prey, 
there  must  be  a  certain  shaped  prominence  for  its  artic- 
ulation ;  a  certain  relation  between  the  position  of  the 
resistance  and  that  of  the  power  with  respect  to  that 
of  the  fulcrum ;  a  certain  magnitude  of  the  muscle  that 
works  the  jaw,  requiring  corresponding  dimensions  of 
the  pit  in  which  that  muscle  is  received,  and  of  the  con- 
vexity of  the  arch  of  bone  beneath  which  it  passes ; 
while  this  arch  must  also  possess  a  certain  amount  of 
strength  to  enable  it  to  bear  the  strain  of  another 
muscle. 

"  That  the  animal  may  be  able  to  carry  off  its  prey, 
a  certain  degree  of  strength  is  necessary  in  the  muscles 
which  support  the  head :  whence  results  a  peculiar 
structure  in  the  vertebra?  to  which  these  mus-cles  are 
attached,  and  in  the  back  of  -the  skull  wnere  they  are 
inserted. 


LECTURES  ON  GEOLOGY.  213 

"  That  the  t3eth  may  be  adapted  to  tear  flesh,  they 
must  be  sharp,  and  they  must  be  more  or  less  so  exactly 
according  as  they  are  likely  to  have  more  or  less  flesh 
to  tear ;  while  their  bases  must  be  strong  in  proportion 
to  the  quantity  of  bone  and  the  magnitude  of  the 
bones  they  have  to  break.  Every  one  of  these  circum- 
stances, also,  will  have  its  effect  on  the  development  of 
all  the  parts  which  assist  in  moving  the  jaw. 

"  That  the  claws  may  be  able  to  seize  the  prey,  there 
must  be  a  certain  amount  of  flexibility  in  the  toes,  and 
of  strength  in  the  nails ;  and  this  requires  a  peculiar 
form  of  the  bones,  and  a  corresponding  distribution  of 
the  muscles  and  tendons.  The  fore-arm  must  possess  a 
certain  facility  in  turning,  whence  also  result  certain 
forms  of  the  bones  of  which  it  is  made  up ;  and  these 
bones  of  the  fore-arm,  articulating  to  the  humerus,  cannot 
undergo  change  without  corresponding  changes  taking 
place  in  this  latter  bone.  The  bones  of  the  shoulder, 
also,  require  to  have  a  certain  degree  of  strength  when 
the  anterior  extremities  are  to  be  used  in  seizing  prey ; 
and  in  this  way,  again,  other  special  forms  become  in- 
volved." 

Thus  the  bony  structure  of  an  animal  corresponds 
exactly  with  the  life  that  it  must  live ;  and  a  man  fa- 
miliar with  the  relation  between  them  can  sometimes, 
from  a  small  fragment,  determine  the  form  of  the  perfect 
animal  and  its  habits.  Seeing  the  track  of  a  cloven 
foot,  we  might  be  sure  that  it  was  made  by  a  ruminating 
mammal ;  and  this  would  give  us  a  knowledge  of  its 
teeth,  jaws,  skull,  vertebras,  pelvis,  and  body. 

Some  of  the  animals  found  in  the  Paris  basin,  Cuvier 
called  paleotheres.  Palaio's  is  the  Greek  for  "  ancient ;  " 
and  therion,  "  animal,"  —  "  ancient  animals ; "  and  well  do 


214  LECTURES  ON  GEOLOGY. 

they  deserve  the  name,  flillions  of  years  have  passed 
since  their  bodies  were  floated  down  some  milky  stream, 
and  deposited  in  the  mud  which  formed  the  gypsum  of 
Montmartre.  They  were  of  various  sizes,  from  that  of 
a  hare  to  that  of  a  horse.  They  more  nearly  resembled 
the  South-American  tapir  than  any  other  existing  animal. 
They  probably  lived  in  rivers,  and  fed  upon  the  plants 
that  grew  on  their  margins.  Along  with  these  have 
been  found  the  remains  of  the  wolf,  fox,  raccoon,  dog, 
opossum,  and  squirrel ;  of  birds,  —  the  buzzard,  owl, 
quail,  woodcock,  curlew,  and  pelican.  Yet,  though  I  call 
up  familiar  animals  by  these  names,  they  do  not  convey 
to  us  the  exact  appearance  of  them  ;  for,  although  they 
belong  to  the  same  genus  as  those  animals,  the  species 
are  all  distinct.  The  dog,  for  instance,  differed  from  the 
living  dog  as  the  wild  cat  differs  from  the  tame,  or  as 
the  ass  differs  from  the  horse. 

Shells  called  nummulites  (from  nummus,  the  Latin  for 
"a  piece  of  money")  are  very  common  in  the  rocks  of  this 
period,  and,  being  found  only  in  tertiary  rocks,  are  a 
very  important  guide  to  the  geologist  in  determining  the 
age  of  many  beds  in  which  they  are  contained. 

"The  nummulitic  formation/'  says  Lyell,  "with  its 
characteristic  fossils,  plays  a  far  more  conspicuous  part 
than  any  other  tertiary  group  in  the  solid  framework  of 
the  earth's  crust,  whether  in  Europe,  Asia,  or  Africa.  It 
often  attains  a  thickness  of  many  thousand  feet,  and 
extends  from  the  Alps  to  the  Carpathians,  and  is  in  full 
force  in  the  north  of  Africa;  as,  for  example,  in  Algeria 
and  Morocco.  It  has  also  been  traced  from  Egypt,  where 
it  was  largely  quarried  of  old  for  the  building  of  the 
Pyramids,  into  Asia  Minor,  and  across  Persia  to  the 
mouths  of  the  Indus.  This  remarkable  formation  enters 


LECTURES  ON  GEOLOGY.  215 

into  the  loftiest  portions  of  the  Alps,  and  has  been  fcund 
in  Western  Thibet  sixteen  thousand  five  hundred  feet 
above  the  level  of  the  sea.'7  The  eocene  limestone  of 
Suggsville,  Ala.,  which  forms  hills  three  hundred  feet 
high,  is  entirely  composed  of  forms  allied  to  them. 

What  a  story  these  small,  circular  shells  tell !  It  is 
evident,  that,  when  they  lived,  the  Alps,  Pyrenees,  Car- 
pathians, and  even  the  lofty  Himalayas,  lay  beneath  the 
ocean,  or  were  but  lifting  their  heads  above  it.  What  a 
difference  there  would  be  between  a  map  of  the  world 
then  and  now  !  And  yet,  before  this  time,  England  had 
long  existed,  and  been  peopled  by  birds  and  beasts  of 
various  kinds. 

The  continent  of  North  America  appears  to  have  been 
slowly  lifted  out  of  the  water  as  one  formation  after 
another  was  laid  down  at  the  bottom  of  the  ocean.  In 
consequence  of  this,  as  we  pass  from  the  mountainous 
portions  of  the  continent  toward  the  sea,  as  a  rule,  we 
pass  over  rocks  more  and  more  recent,  till  we  arrive  at 
the  coast.  The  formations  thus  extend  in  belts  widening 
toward  the  west  along  the  Atlantic  States. 

South  of  the  cretaceous  formation,  along  the  Atlantic 
border,  from  Delaware  and  Maryland  to  Georgia  and 
Alabama,  we  find  an  eocene  belt,  widening  as  we  go 
south  and  west.  The  beds  are  composed  of  sand,  marl, 
clay,  and  sandstones,  and  limestones  abounding  with 
fossils.  At  Claiborne,  Ala.,  four  hundred  species  of 
shells  and  remains  of  echini  and  fishes  have  been  found. 
In  Clarke  County,  in  the  same  State,  have  been  found 
immense  bones  belonging  to  a  sea-monster  called  the 
zeuglodon,  or  yoke-tooth,  from  the  yoke-like  appearance 
of  its  teeth.  Some  of  its  vertebras  are  so  heavy,  that 
they  are  a  load  for  a  man  to  carry ;  and  its  length  was  at 


216  LECTURES  ON  GEOLOGY. 

least  seventy  feet.  So  numerous  are  they,  that  Lyell 
says,  "I  obtained  evidence,  during  a  short  excursion,  of 
so  many  localities  of  this  fossil  animal  within  a  distance 
of  ten  miles,  as  to  lead  me  to  conclude  that  they  must 
have  belonged  .to  at  least  forty  distinct  individuals." 

It  was  at  first  supposed  to  be  a  lizard,  and  was  named 
basilosaurus,  or  king  of  lizards ;  but  it  is  now  known  as  a 
mammal  of  the  whale  kind,  and  therefore  a  member  of 
the  order  cetacea.  It  somewhat  resembled  the  manatus, 
or  sea-cow.  Animals  of  the  same  genus  have  been  found 
in  miocene  beds  of  France,  Germany,  and  Malta. 

Somewhat  older  than  the  beds  containing  the  zenglo- 
don,  though  frequently  regarded  as  more  recent,  is  a 
deposit  at  Brandon,  in  Vermont,  consisting  of  clay  and 
gravel  and  (lying  in  these  in  irregular  bodies)  manga- 
nese, iron-ore,  and  lignite  or  brown  coal.  In  the  brown- 
coal  bed  have  been  found  bushels  of  fossil  fruits,  most 
of  them  nuts.  Among  the  fruits  have  been  recognized 
some  that  resemble  the  cinnamon,  the  fig,  and  the  grape. 

The  climate  of  Vermont  during  the  eocene  period  was 
evidently  warm,  though,  as  its  flora,  or  plants,  indicate, 
hot  as  much  so  as  in  places  of  corresponding  latitude  in 
Europe :  thus  early,  that  difference  in  climate  which  ex- 
ists between  the  two  continents  made  its  appearance. 

There  was,  doubtless,  a  teeming  fauna,  or  assemblage 
of  animals,  feeding  on  the  fruitful  spice-forests  of  eocene 
Vermont ;  but  the  first  fragment  has  yet  to  be  discovered. 

Miocene.  —  The  beds  of  the  miocene,  or  middle  tertiary, 
are  not  found  in  England,  but  are  well  developed  in 
Europe  and  America.  The  vegetation  indicates  a  cooler 
climate  than  the  preceding  periods,  though  still  warmer 
than  exists  in  the  same  latitude  at  the  present  day. 
Tropical  palms,  bamboos,  and  laurels  grew  in  Europe, 


LECTURES  ON  GEOLOGY. 


217 


and  with  them  the  maples,  walnuts,  beeches,  elms,  and 
oaks  of  a  temperate  clime. 

In  Nebraska,  and  the  country  of  the  Upper  Missouri, 
is  a  remarkable  region,  called  by  the  French  mauvaises 
terr€sy  or  "  bad  lands.''  It  consists  of  immense  beds  of 
clay  which  have  been  carved  by  running  streams  flowing 
through  numerous  winding  channels,  and  causing  the 
portions  left  in  relief  to  assume  the  appearance  of  fantas- 
tic ruins.  The  region  is  thus  described  by  David  Dale 
Owen  :  — 

"  From  the  uniform,  monotonous,  open  prairie,  the 
traveller  suddenly  descends  one  or  two  hundred  feet 
into  a  valley  that  looks  as  if  it  had  sunk  away  from  the 
surrounding  world,  leaving  standing  all  over  it  thousands 
of  abrupt,  irregular,  prismatic,  and  columnar  masses,  fre- 
quently capped  with  irregular  pyramids,  and  stretching 
up  to  a  height  of  from  one  to  two  hundred  feet  or  more. 

"  So  thickly  are  these  natural  towers  studded  over  the 
surface  of  this  extraordinary  region,  that  the  traveller 
threads  his  way  through  deep,  confined,  labyrinthine  pas- 
sages not  unlike  the 
narrow,  irregular 
streets  and  lanes  of 
some  quaint  old  town 
of  the  European  con- 
tinent," 

Numerous  fossils, 
once  embedded  in 
the  clay,  have  been 
washed  out,  and  ob- 
tained ;  among  them,  Testudo  hemispherica. 

many  turtles.      Fig.   41,  from   this  region,   derives   its 
name    from   its   hemispherical    shape.     The  weight    of 


Fig.  41. 


218  LECTURES   ON  GEOLOGY. 

some  specimens  now  lying  there  has  been  estimated 
at  a  ton.  The  tertiary  period  seems  to  have  been  emi- 
nently favorable  for  turtles,  especially  the  early  part,  of 
it :  most  deposits  of  that  age  contain  remains  of  them. 
They  basked  on  the  logs  that  lay  in  the  rivers ;  they 
floated  on  the  tepid  waters  of  the  shallow  lakes ;  they 
made  paths  along  the  sandy  shores  to  their  nests,  where 
eggs  innumerable  were  buried,  from  which  new  broods 
were  continually  raised. 

Forty  species  of  extinct  mammals  have  been  discov- 
ered in  the  beds  of  the  mauvaises  terres:  eight  of  them 
carnivorous,  or  flesh-eaters,  and  related  to  the  hyena,  dog, 
and  panther;  and  twenty-five  herbivorous,  or  vegetable- 
feeders,  and  resembling  the  deer,  hog,  camel,  and  horse. 
The  jaw  of  one  paleothere  (resembling  those  of  the 
Paris  basin,  but  larger)  measures  five  feet  along  the 
range  of  the  teeth.  It  was  twice  as  large  as  a  horse. 
One  skeleton  measures  eighteen  feet  long,  and  nine 
high.  One  species,  styled  arclieotlierium,  unites  charac- 
ters belonging  to  three  orders :  the  molar  teeth  are  con- 
structed after  the  model  of  the  hog  ;  the  canine  teeth  are 
like  those  of  the  bear  ;  while  the  upper  part  of  the  skull 
and  cheek-bones  have  the  form  and  dimensions  of  the 
cat  tribe. 

The  oreodon,  another  extinct  form  from  these  beds, 
has  grinding  teeth  like  the  elk  and  deer,  and  canine 
teeth  resembling  the  hog.  They  were  animals,  it  is 
supposed,  that  lived  on  flesh  and  vegetables,  and  yet 
chewed  the  cud. 

That  portion  of  Nebraska  must  have  been  covered  by 
a  shallow  and  probably  brackish  lake  during  this  time, 
having  rivers  pouring  in  turbid  torrents,  and  sweeping 
down  the  remains  of  the  various  animals  living  where 


LECTURES   ON  GEOLOGY.  219 

their  waters  ran :  thus  they  became  mingled  with  the 
remains  of  the  turtles,  the  inhabitants  of  the  lake. 

Near  the  junction  of  White  and  Green  Rivers,  partly 
in  Colorado,  and  partly  in  Utah,  is  an  immense  tertiary 
deposit,  which  I  regard  as  miocene.  It  consists  of  a 
series  of  petroleum  shales,  a  thousand  feet  in  thickness, 
varying  in  color  from  that  of  cream  to  the  blackness  of 
cannel-coal.  The  shales  abound  in  impressions  of  leaves 
and  of  various  species  of  insects. 

Fossil  insects  are  rare,  considering  that  at  the  present 
time  insects  are  the  most  numerous  of  all  animated 
forms.  A.  few  fragments  have  been  obtained  from  the 
Devonian  rocks  of  New  Brunswick,  and  more  numerous 
fragments  from  the  carboniferous  beds  of  England,  Nova 
Scotia,  and  Illinois.  At  Solenhofen,  in  Bavaria, -very  per- 

Fig  42. 


JEsehna  eximia. 


feet  specimens  have  been  found;  among  them  a  beautiful 
dragon-fly  (Fig.  42),  which  measures  from  tip  to  tip  six 


220  LECTURES   ON  GEOLOGY. 

inches.  In  the  lower  lias  of  "England,  several  bands  of 
limestone  occur,  which  are  crowded  with  the  win^-casea 
of  beetles,  and  occasionally  perfect  insects,  and  hence  are 
known  by  the  name  of  "  insect  limestones."  But  I  think 
there  is  no  part  of  the  world  known  where  fossil  insects 
are  as  numerous  and  as  perfect  as  in  the  petroleum 
shales  of  the  White-river  basin.  The  collection  that  I 
brought  from  there  was  placed  in  the  hands  of  Mr.  S.  II. 
Scudder,  Secretary  of  the  Boston  Natural-history  So- 
ciety, whose  knowledge  of  this  much-neglected  branch 
of  paleontology  is  probably  greater  than  that  of  any 
other  American.  He  says  the  collection  consists  of 
between  sixty  and  seventy  species  of  insects,  represent- 
ing nearly  all  the  different  orders.  "  About  two-thirds  of 
the  species  are  flies,  —  some  of  them  the  perfect  insect, 
others  the  maggot-like  larvae.  The  greater  part  of  the 
beetles  were  quite  small.  There  were  three  or  four  kinds 
of  homoptera  (allied  to  the  tree-hoppers),  ants  of  two 
different  kinds  of  genera,  and  a  poorly-preserved  moth. 
Perhaps  a  minute  thrips,  belonging  to  a  group  which 
has  never  before  been  found  fossil  in  any  part  of  the 
world,  is  of  the  greatest  interest.  At  the  present  day, 
these  tiny  and  almost  microscopic  insects  live  among  the 
petals  of  flowers  ;  and  one  species  is  supposed  by  some 
entomologists  to  be  injurious  to  the  wheat."  Mr.  Scud- 
der adds,  "  It  is  astonishing  that  an  insect  so  delicate 
and  insignificant  in  size  can  be  so  perfectly  preserved 
on  these  stones.  In  the  best  specimens,  the  body  is 
crushed  and  displaced,  yet  the  wings  remain  uninjured; 
and  every  hair  of  their  broad  but  microscopic  fringe  can 
be  counted." 

I  brought  the  specimens  from  two  localities, — one 
in  Utah,  near  the  mouth  of  White  River  j  and  the  other 


LECTURES  ON  GEOLOGY.  221 

about  sixty  miles  up  the  stream,  in  Colorado.  I  have  no 
doubt  that  the  insect  shales  extend  from  the  one  locality 
to  the  other,  and  cover  hundreds  of  square  miles,  in  a 
country  where  the  rocks  are  exposed  by  denudation  in 
ten  thousand  places.  Future  explorers  will  find  rich 
harvests  in  this  highly  interesting  region. 

Above  the  shales  containing  the  insects  are  alter- 
nating beds  of  sandstone,  shale,  and  conglomerate,  not  less 
than  a  thousand  feet  in  thickness.  In  the  conglomerate 
beds  are  rolled  fragments  of  bones  of  large  mammals, 
generally  solid ;  and  in  the  sandstones  perfect  turtles, 
having  shells  of  great  thickness  and  denseness.  The 
country  formed  of  these  beds  is  one  of  the  most  remark- 
able on  this  continent.  From  the  summit  of  a  high 
ridge  on  the  east,  a  tract  of  country  containing  five  or 
six  hundred  square  miles  is  distinctly  visible.  Over  the 
whole  surface  is  rock,  bare  rock,  cut  into  ravines,  can- 
yons, gorges,  and  valleys;  leaving  in* magnificent  relief 
terrace  upon  terrace,  pyramid  beyond  pyramid,  rising 
to  mountain-heights,  and  these  pyramids  ruled  with  deli- 
cate lines  from  base  to  summit,  caused  by  the  stratifi- 
cation of  the  shales  of  which  they  are  composed ; 
amphitheatres  that  would  hold  a  million  spectators ; 
Titanic  walls,  castles,  towers,  pillars,  statues,  every- 
where.  It  looks  like  some  ruined  city  of  the  gods, 
blasted,  bare,  desolate,  but  grand  beyond  description. 
Originally  an  elevated  country,  composed  of  a  number  of 
beds  of  sandstone,  conglomerate,  and  shale,  of  varying 
thickness  and  hardness,  it  has  been  worn  down  and  cut 
'out  by  rills,  creeks,  and  streams,  leaving  this  strange 
weird  country  to  be  the  wonder  of  all  generations. 

During  the  time  that  these  beds  were  being  deposited, 
a  large  basin  occupied  by  a  lake,  or,  more  probably, 


222  LECTURES  ON  GEOLOGY. 

several  connected  lakes,  covered  Western  Colorado,  and 
extended  into  Utah  and  Arizona.  Into  them  flowed 
numerous  streams,  carrying  down  fine  mud,  and  at 
times  petroleum  in  large  quantities,  probably  flowing 
from  numerous  springs.  The  land  was  covered  with 
trees  resembling  the  oak,  maple,  and  willow;  though 
other  forms  that  existed  are  now  extinct.  Insects  by 
myriads  hovered  around  the  margins  of  the  lakes,  and 
their  larvae  swarmed  in  the  peaceful  waters ;  turtles 
abounded  ;  and  aquatic  pachyderms  sported  among  the 
reeds,  and  bathed  in  the  lakes,  some  feeding  upon  the 
fish,  and  others  on  the  numerous  plants  that  sprang  from 
their  muddy  bottoms.  The  water  was  probably  salt,  or 
at  least  brackish ;  the  present  Salt  Lake  of  Utah  being 
a  modern  representative  of  these  older  and  larger  lakes, 
into  which  rivers  poured  mud,  sand,  and  pebbles,  sweep- 
ing down  leaves,  branches,  and  occasionally  trunks  of 
trees  and  skeletons,  till  the  shales,  sandstones,  and  con- 
glomerates of  the  White-river  basin  were  formed. 

The  miocene  formation  is  well 
represented  in  the  Atlantic  States 
by  beds  of  marl,  clay,  sand,  lime- 
stone, sandstone,  and  lignite.  At 
Martha's  Vineyard  in  Massachu- 
setts, and  in  a  belt  from  New  Jer- 
sey along  the  Atlantic  border  to 
South  Carolina,  miocene  beds  are 
found.  They  contain  a  great  abun- 
dance of  shells,  of  which  from  ten 
to  forty  per  cent  are  of  living 
grains,  species.  Some  of  them  are  solid 

masses  of  broken  shells.  Fig.  43  represents  one  of  the 
tenebratulae  of  this  time.  This  mollusk  was  furnished 


LECTURES  ON  GEOLOGY.  223 

with  a  muscular  arm,  or  pedicle,  which  it  protruded 
through  the  hole  at  the  end  of  the  shell,  and  thus 
anchored  to  surrounding  objects. 

Professor  Heer  has  discovered  in  the  miocene  beds 
of  Northern  Greenland  the  fir,  poplar,  beech,  plane, 
hazel,  and  other  plants  that  are  now  only  to  be  found 
eiirht  or  nine  hundred  miles  to  the  south.  The  most 

o 

common  tree  appears  to  have  been  one  allied  to  the  red- 
wood of  California,  which  sometimes  attains  a  height  of 
two  hundred  and  seventy-five  feet,  and  a  diameter  of 
twenty.  The  climate  of  Greenland  must  have  greatly 
changed  since  such.vegetation  flourished  there. 

In  the  neighborhood  of  (Eningen,  near  Constance,  in 
Germany,  are  miocene  beds  of  marls,  limestone,  and 
lignite  or  imperfect  coal.  The  Rhine  flows  through 
them,  exposing  beds  on  both  sides  in  cliffs  from  seven 
hundred  to  nine  hundred  feet  in  height.  In  these  beds 

Fig.  44. 


Galecynus  (Eningensis. 


have  been  found  leaves  of  the  poplar,  willow,  maple,  lin« 
den,  and  elm.     The  buckthorn  has  also  been  found,  and 


224  LECTURES  ON  GEOLOGY. 

what  is  supposed  to  be  a  species  of  wheat.  In  the  same 
beds  have  been  found  insects,  shells,  fishes,  turtles,  tor- 
toises, birds,  and  an  animal  resembling  the  common  fox, 
'  Galecynus  (Eningensis  (weasel-dog  of  (Eningen),  Fig  44. 
Owen  gives  it  an  intermediate  position  between  the 
r>ole-cat  and  dog. 

Amber  has  been  found  in  the  beds  at  Martha's  Vine- 
yard and  at  Brandon  ;  but  the  greatest  amount  has  been 
obtained  on  the  shores  of  the  Baltic,  washed  out  of  the 
lignite  beds  by  the  waves.  Species  of  pines  existed, 
from  which  gum,  or  resin,  flowed.;  and,  becoming  fossil- 
ized, amber  was  the  result.  In  flowing  down  the  tree, 
insects,  spiders,  small  crustaceans,  and  leaves  were 
covered;  and  thus  we  find  them  preserved  in  the  trans- 
parent amber.  Upwards  of  eight  hundred  species  of 
insects  have  been  observed,  and  eight  species  of  conif- 
erous trees,  or  trees  bearing  cones  like  the  pine, 
with  "  several  cypresses,  yews,  junipers,  oaks,  poplars, 
beeches,  &c. ;  altogether  ninety-eight  recognizable  spe- 
cies of  trees  and  shrubs.  There  are  also  some  fern&, 
and  numerous  mosses,  fungi,  and  liverworts." 

Fish  remains  have  been  found  in  great  abundance  in 
miocene  beds;  among  them  teeth  of  sharks,  larger  than 
a  man's  hand.  Sharks  must  have  occasionally  attained 
the  size  of  large  whales  ;  and  this  indicates  a  great  abun- 
dance of  the  small  fish  on  which  they  fed. 

At  Monte  Bolca,  in  Italy,  is  a  hill  composed  of  limy 
shales  which  abound  in  fishes  in  the  most  beautiful  state 
of  preservation;  the  scales,  bones,  fins,  and  even  the 
muscular  tissues,  being  frequently  preserved.  Several 
hundred  species  have  been  found  there,  and  thousands 
of  specimens  carried  off  to  enrich  cabinets  :  still  millions 
remain.  "Prom  the  immense  quantities,"  says  Dr. 


LECTURES   ON   GEOLOGY.  225 

Marrtell,  "  which  occur  in  so  limited  an  area,  it  seems 
probable  that  the  limestone  in  which  they  ar<i  embedded 
was  a  lirny  mud  erupted  into  the  ocean  by  volcanic 
agency,  and  that  the  fishes  were  thus  suffocated  and 
surrounded  by  the  calcareous  mass."  This  is  very 
likely ;  and  such  catastrophes  must  have  taken  place 
times  innumerable.  Life  over  limited  areas  destroyed  ; 
the  relics  of  life  deep  buried  at  times,  at  others  left  to 
decompose,  and  leave  no  visible  trace  behind,  again  to 
be  renewed,  and  again  destroyed  and  renewed,  —  these 
to  continue  till  the  Earth  shall  attain  her  perfect  con- 
dition, and  peace  and  order  reign  everywhere. 

At  (Eniogen,  already  mentioned,  in  1725  a  remark- 
able skeleton  was  discovered  (Fig.  45).  It  was  exam- 
ined by  Scheuchzer,  a  Swiss  Fig  45> 
naturalist,  who  supposed  it  to 
be  the  skeleton  of  a  man,  and 
gave  a  description  of  it  in  the 
Philosophical  Transactions  of 
London.  In  1731,  he  published 
a  pamphlet  in  reference  to  it,  and 
entitled  it  "  Man's  Testimony  to 
the  Deluge."  He  says,  "  It  is 
certain  that  this  is  the  half,  or 
nearly  so,  of  the  skeleton  of  a 
man ;  that  the  substance  even 
of  the  bones,  and,  what  is  more, 
of  the  flesh,  and  of  parts  still 
softer  than  the  flesh,  are  there 
incorporated  in  the  stone ;  in  a 
word,  i't  is  one  of  the  rarest 
relics  which  we  have  of  that  .  Andr"s  ' 
cursed  race  which  was  buried  under  the  waters."  Ha 

16 


226  LECTURES  ON  GEOLOGY. 

even  says  that  there  were  remains  of  the  brain,  the 
roots  rf  the  nose,  and  some  vestiges  of  the  liver.  Cam- 
per, a  celebrated  naturalist  of  Holland,  examined  it,  and 
saw  a:  once  that  it  was  not  a  man,  but  supposed  it  to  be 
a  lizard.  The  matter  was  decided  by  Cuvier,  who  pro- 
nounced it  a  large  salamander ;  and  thus  perished  the 
"  witness  of  the  Deluge." 

One  of  the  most  remarkable  mammals  of  this  time  was 
the  deinotherium,  or  fearful  beast.  The  name  is  derived 
from  the  Greek  deinos,  "  fearful  or  terrible,"  and  therion, 
11  beast,  or  animal."  It  was  of  enormous  size  and  peculiar 
appearance,  but,  being  a  vegetable  feeder,  was  probably 
harmless.  Its  remains  are  found  in  the  Valley  of  the 
Rhine,  near  Darmstadt,  and  in  the  Valleys  of  the  Jura 
Mountains,  and  particularly  at  Eppelsheim,  in  Hesse 
Darmstadt,  where  thirty  other  species  of  fossil  mammals 
have  been  found.  An  entire  head  of  the  deinotherium 
was  found  there,  which  measured  four  feet  in  length,  and 
three  feet  in  breadth ;  while  the  whole  length  of  the 
animal  was  calculated  by  Cuvier  to  be  eighteen  i'eet. 
The  head  was  furnished  with  a  proboscis,  and  two  large 
tusks  in  the  lower  jaw  which  were  curved  downwards. 
Dr.  Buckland  supposed  that  it  lived  in  the  water,  float- 
ing its  enormous  body  upon  the  surface,  and  using  its 
tusks  as  pickaxes  to  grub  up  the  roots  on  which  it  fed, 
and  as  anchors  attached  to  the  bank  to  support  its  head 
while  it  slept.  The)71  seem  to  be  linking  forms  between 
the  sea  mammalia  and  the  land. 

At  the  same  place  have  been  found  bones  of  the 
mastodon,  which  in  various  species  during  the  remainder 
of  the  tertiary  period,  and  even  as  recently  as  the 
human  period,  roamed  over  America,  Europe,  and  Asia. 
This  animal  resembled  the  elephant,  but  was  larger ;  his 


LECTURES  ON  GEOLOGY.  227 

body  being  longer,  and  his  limbs  more  massive.  The 
teeth  also  were  different,  having  conical  eminences  cov. 
ered  with  enamel :  hence  its  name,  from  mastos,  "  nipple," 
and  odous,  "  tooth.'7 

Six  mastodon  skeletons  were  found  in  Warren  County, 
New  Jersey,  by  a  farmer  who  was  digging  mud  from  a 
small  pond.  Within  the  ribs  of  one,  just  where  the 
stomach  must  have  been,  seven  bushels  of  vegetable 
matter  were  extracted  :  some  of  it,  upon  examination, 
proved  to  be  shoots  of  the  cedar.  Within  the  ribs  of 
mastodons  found  in  other  localities  have  been  found 
masses  of  small  branches,  leaves,  grass,  and  reeds  in  a 
half-bruised  state ;  but  these  animals  must  have  existed, 
geologically  speaking,  within  a  recent  period. 

Tusks  have  been  found  measuring  from  twelve  to  four- 
teen feet  in  length.  Imagine  them  !  —  white,  smooth, 
curved,  massive,  a  black  trunk  swinging  between  them, 
or  stretched  to  an  overhanging  branch;  back  of  these 
an  enormous  head,  long,  high,  and  arched,  furnished  with 
teeth  weighing  from  ten  to  twelve  pounds  ;  with  flapping 
ears,  large  as  a  blacksmith's  leather  apron,  attached  to  a 
stack  of  flesh  covered  with  a  thick  skin,  and  supported 
on  legs  like  huge  pillars.  Multiply  it  by  twenty,  and 
you  have  a  herd  of  mighty  mastodons,  such  as  wandered 
through  the  woods  of  Missouri  and  Kansas  before  the 
prairies  began  to  be.  Now  they  feed  at  the  edge  of  the 
forest,  tearing  down  the  branches  with  their  trunks,  ever 
and  anon  trumpeting  to  their  comrades  in  a  neighboring 
forest,  whose  answer  sounds  like  the  mutterings  of  dis- 
tant thunder.  Away  they  go  crashing  through  the 
woods,  the  young  ones  waddling  after  them,  tearing  up 
good-sized  trees  by  the  roots  as  they  pass,  for  sport, 
down  to  the  lake,  and  bathe  their  bare,  black  sides,  while 


228  LECTURES  ON  GEOLOGY. 

# 

from  their  trunks  they  send  up  fountains  of  water.  In 
the  distance,  see  that  pack  of  wild  dogs  hunting  like 
wolves  i  What  are  they  pursuing  ?  A  herd  of  wild  horses. 
Hear  them  snort  with  fear,  and  see  them  toss  their  manes, 
as  they  go  flying  like  the  wind,  with  these  gaunt  dogs  in 
full  pursuit!  Tapir-like  animals  are  bathing  in  the  rivers, 
and  sloths  hang  from  the  branches  of  far-spreading  trees ; 
grasses  cover  large  beaver-meadows ;  while  monkeys, 
the  most  intelligent  onlookers,  chatter  to  each  other  on 
the  surrounding  trees,  and  leap  from  bough  to  bough. 

The  fossil  horse  has  been  found  in  various  tertiary 
beds,  ranging  from  the  miocene  to  the  drift,  in  France, 
Germany,  Malta,  India,  and  America  from  New  England 
to  Patagonia.  Those  found  in  the  miocene  generally 
differ  from  the  existing  horse  in  the  distribution  of  the 
enamel  of  the  tooth,  and  in  the  possession  of  two  small 
digits  and  hoofs,  which  dangled  by  the  side  of  the  large 
one.  They  appear  to  have  been  transitional  forms  be- 
tween the  paleotheres  of  the  eocene  and  the  horse  of 
the  present. 

Though  the  horse  was  common  on  the  American  conti- 
nent during  the  tertiary,  yet,  when  the  Spaniards  first 
came  here,  there  was  no  animal  of  the  horse  kind  in 
America.  The  Indians  had  never  seen  one ;  and  they 
supposed,  when  they  saw  the  Spaniards  on  horseback, 
that  horse  and  man  were  all  one  animal. 

One  by  one,  old  forms  die  out.  The  trilobites  of  the 
early  times  disappeared,  one  generation  after  another 
flourishing  and  decaying,  till  the  last  vanished ;  the  am- 
monites of  the  oolitic  and  cretaceous  periods,  the  great 
reptiles,  and  the  flying  pterodactyles,  flourished,  lingered, 
and  died ;  and  so  the  mastodons,  camels,  and  horses  of 
America.  As  the  leaves  of  evergreens  constantly  drop, 


LECTURES  ON  GEOLOGY.  229 

and  new  ones  supplant  them :  so  with  the  great  tree  of 
life  j  the  species  as  leaves  dropped,  and  new  ones  gradu- 
ally supplanted  them,  so  that  it  is  only  by  looking  back 
over  immense  periods  that  we  can  see  the  great  changes 
thus  produced. 

There  were  many  mammalian  forms  existing  during  the 
miocene  period,  whose  living  appearance  would  startle 
us  considerably.  Between  the  River  Sutlej  and  the 
Ganges,  in  India,  is  a  tertiary  deposit,  consisting  of  beds 
of  conglomerate,  sandstone,  and  loam,  spread  over  the 
flanks  of  a  range  of  hills  belonging  to  the  sub-Hima- 
layan Mountains,  known  as  the  Sewalik  Hills.  In  these 
have  been  found  paleotheres,  elephants,  mastodons, 
giraffes,  rhinoceroses,  camels,  antelopes,  and  monkeys, 
birds  of  the  ostrich  kind,  crocodiles,  and  tortoises. 

The  most  remarkable,  perhaps,  among  this  wonderful 
assemblage  of  animals,  is  the  rivatherium,  deriving  its 
name  from  the  Indian  god  Siva.  .  It  was  as  large  as  an 
elephant,  and  probably  taller ;  and  seems  to  have  been  a 
link  between  it  and  the  ruminants,  or  cud-chewers,  —  an 
elephantine  stag.  It  had  four  horns,  and  was  furnished 
with  a  proboscis.  One  pair  of  the  horns  wras  short,  and 
placed  forward  above  the  eyes ;  the  other  pair  broad 
and  long,  like  those  of  the  elk,  rising  above  the  ears.  It 
had  small  eyes  and  great  lips. 

Among  various  reptilian  remains,  including  turtles  and 
crocodiles,  some  of  which  cannot  be  distinguished  from 
species  now  living  in  India,  are  the  bones,  and  portions 
of  the  shell,  of  a  gigantic  tortoise,  not  less  than  twenty 
feet  in  length. 

The  tertiary  formation  has  a  remarkable  development 
in  Colorado.  I  estimate  its  thickness,  from  the  top  of 
the  Parahlamoosh  Range  (which  lies  west  of  Middle  Park, 


230  LECTURES   ON   GEOLOGY. 

and  is  composed  of  tertiary  lavas,  probably  of  miocene 
age)  to  the  junction  of  White  and  Green  Rivers,  at  ten 
thousand  feet.  Included  in  this  are  coal-measures, 
containing  many  beds  of  coal,  underclays,  sandstones, 
shales,  and  thin  limestones,  having  a  total  thickness  of 
twenty-four  hundred  feet.  The  lavas  of  the  Parah- 
lamoosh,  with  their  alternating  beds  of  sandstone,  cannot, 
I  think,  be  less  than  four  thousand  feet  in  thickness. 
Since  their  deposition,  the  range  must  have  been  great- 
ly elevated,  as  it  is  now  thirteen  thousand  feet  above 
the  sea-level;  and  yet  its  beds  are  apparently  horizontal. 
The  lavas  that  formed  them  were  evidently  poured  out 
on  the  bottom  of  a  lake,  or  inland  sea,  covering  the 
sand  that  lay  there,  and  in  some  cases  penetrating  it  to 
a  depth  of  ten  or  twelve  feet.  Between  some  of  the 
outpourings,  sand  was  swept  down  over  the  lava,  cover- 
ing it,  in  places,  to  a  depth  of  more  than  a  hundred 
feet ;  then  another  layer  was  poured  out  over  this ;  and 
so  on  for  thousands  of  feet. 

In  the  Middle  Park,  Colorado,  are  a  series  of  beds, 
which  I  have  called  baculite  beds,  from  the  abundance 
of  baculites  contained  in  them.  They  are  associated  with 
gasteropods  and  conchs,  that  resemble  tertiary  fossils 
much  more  than  they  do  cretaceous,  although  the 
baculite  is  characteristic  of  the  upper  chalk  in  England 
and  on  the  continent  of  Europe.  These  beds  belong,  I 
think,  to  the  eocene  period.  They  are  succeeded  by 
shaly  sandstones  four  hundred  feet  thick,  abounding  with 
the  impressions  of  the  scales  of  cycloidal  fishes ;  that 
is,  fishes  whose  scales  resemble  those  of  the  salmon,  the 
trout,  and  most  of  our  modern  fishes :  but  although  the 
scales  are  so  numerous,  and  some  of  them  an  inch  in 
diameter,  not  a  tooth  was  discoverable. 


LECTURES   ON   GEOLOGY.  231 

Above  these  sandstones  are  other  sandstones  and 
conglomerates,  about  four  hundred  feet  in  thickness, 
abounding  in  fragments  of  silicified  wood  and  occasional 
bones,  probably  of  recent  miocene  age ;  and  above  these 
are  beds  of  lava,  about  two  hundred  feet  in  thickness, 
containing  moss-agates,  and  geodes  of  chalcedony,  which, 
where  the  beds  have  been  disintegrated,  strew  the 
ground. 

At  the  foot  of  the  Rocky  Mountains,  on  the  east,  is  a 
deposit  of  tertiary  coal,  or  lignite,  which  burns  readily,  but 
will  not  coke.  At  Golden  City,  twelve  miles  west  of 
Denver,  one  bed  has  been  opened  which  has  a  thickness 
of  from  ten  to  twelve  feet.  Owing  to  upheaval,  this 
bed,  with  its  accompanying  shales  and  sandstones,  stands 
nearly  vertical.  About  twenty  miles  north  of  Denver,  on 
Coal  Creek,  there  are  several  exposures  of  coal  alter- 
nating with  beds  of  iron-ore  and  sandstones,  resembling 
very  much  the  beds  of  the  Welsh  coal-measures  from 
which  most  of  the  iron  of  Great  Britain  is  produced. 

It  is  not  difficult,  with  the  discoveries  already  made 
in  Colorado,  to  call  up  the  country  as  it  existed  on  the 
eastern  side  of  the  mountains  about  the  close  of  the 
miocene  period,  after  the  deposition  of  the  lignite  beds ; 
the  mountain -chain  then  probably  less  elevated,  des- 
titute of  its  snowy  crown,  and  clad  with  coniferous 
trees  to  its  summit  everywhere.  Immediately  west  of 
Golden  City  were  immense  forests  of  lordly  trees,  the 
growth  of  ages ;  some  palms ;  some  resinous  and  gum- 
bearing  trees  of  strange  aspect,  on  which  fed  lordly 
mastodons,  while  sloths  hung  from  their  branches  by 
their  long  claws-  as  they  ate  the  foliage. 

Below  was  a  long  and  wide  lake,  covering  the  spot 
where  Golden  City  and  Denver  now  stand,  and  stretch- 


232  LECTURES  ON  GEOLOGY. 

ing  north  and  south  for  an -immense  distance.  From  the 
charactei  of  the  surrounding  country,  this  lake'  must 
have  been  ctear  as  crystal ;  and  we  may  see  the  fish  that 
bathe  in  its  pellucid  waters,  the  turtles  that  crawl  at  the 
bottom  or  lazily  float  on  the  top,  while  alligators  fight 
with  each  other,  and  seize  the  fish  that  constitute  their 
prey.  Mountain-goats,  with  their  long,  recurved  horns, 
look  down  from  the  rocky  crag  that  juts  over  the  lake ; 
and  the  wading-birds  feed  upon  fish  and  frogs,  its  in- 
numerable tenants. 

The  remains  of  palms  and  resinous  trees  are  very 
abundant  along  the  base  of  the  mountains  on  the  eastern 
side  for  a  great  distance.  Hot-springs  charged  with 
silica  poured  out  their  waters,  which  percolated  through 
the  sand-beds  containing  the  remains  of  trees  washed 
down  by  the  mountain-torrents  ;  and  the  face  of  the 
country,  in  some  localities,  is  absolutely  covered  with 
fossil  wood  thus  produced :  for  the  land  became  the 
theatre  of  widespread  and  intense  volcanic  action,  as 
indicated  by  trap  deposits  in  Middle  Park,  near  Golden 
City,  on  the  eastern  side  of  the  range,  and  outlying 
masses,  probably  once  connected  from  there  to  the 
Huerfano  River,  one  of  the  branches  of  the  Arkansas. 
These  were  probably  produced  by  one  of  the  last  up- 
heavals of  the  Rocky -mountain  chain ;  the  drainage  of 
the  lakes  following,  and  the  production  of  innumerable 
hot-springs,  whose  effects  can  be  traced  over  so  large  a 
district  on  both  sides  of  the  range. 

Two  species  of  monkeys  have  been  discovered  in  the 
miocene  of  Southern  France.  They  resemble  the  genus 
hylobates,  or  long-armed  apes  of  India.  •  Of  three  species 
found  in  the  Sewalik  Hills,  two  resemble  the  present 
solemn  ape  of  India,  and  the  third  the  common  Indian 


LECTURES  ON  GEOLOGY.  233 

monkey;  but  all  were  of  larger  size  than  existing 
species.  At  Pikermi,  in  Greece,  M.  Gaudry  has  recently 
discovered  the  remains  of  fifty-one  species  of  animals, 
all  of  which  are  extinct.  Among  them  were  twenty- 
five  monkeys  belonging  to  one  species.  The  animals 
found  are  somewhat  African  in  type,  and  show  that 
Greece  was  intimately  connected  with  Africa  during 
miocene  times. 

Pliocene.  —  With  hasty  steps  we  approach  the  period 
of  the  present ;  and  at  every  step  changes  are  manifested 
which  are  of  great  interest  to  the  observer.  During  the 
tertiary  period,  the  Rocky  Mountains  were  gradually 
uplifted  several  thousand  feet,  attaining,  probably,  a 
greater  height  than  they  at  present  possess.  Out  of  the 
water  have  been  heaved  the  Andes,  the  backbone  of 
South  America,  the  Alps,  and  the  Himalayas,  the  mighty 
crests  of  Europe  and  Asia;  lakes  have  been  drained; 
immense  plains  wrested  from  the  waters ;  and  now  the 
land-surface  of  the  globe  becomes  very  similar  in  outline 
to  that  with  which  we  are  familiar.  The  climate  is 
cooler ;  the  palms  that  flourished  so  abundantly  in  Europe 
disappear,  and  are  succeeded  by  the  vegetation  of  a 
more  temperate  clime.  The  shells  found  abundantly  in 
many  of  the  beds  are  similar  to  those  of  our  present  seas, 
being  from  seventy  to  ninety  per 
cent  modern. 

In  Suffolk,  England,  there  is  a 
well-marked  group  of  rocks  belong- 
ing to  this  formation,  known  by 
the  name  of  the  "  Suffolk  Crag."  Fu8US  antiiuus- 

One  portion  of  it,  called  the  Coralline  Crag,  is  almost 
entirely  made  up  of  coral ;  though  shells,  sponges,  and 
echini  are  distributed  through  it.  One  very  character- 


234  LECTURES  ON  GEOLOGY. 

istic  shell  of  the  upper  crag  is  the  Fusus  antiquus  (Fig. 
46),  which  is  associated  with  shells  belonging  to  genera 
now  existing  in  temperate  zones.  Those  which  are  pe- 
culiar to  tropical  climates  are  either  absent  or  of  small 
size.  About  four  hundred  and  fifty  species  of  shells 
have  been  found  in  the  Suffolk  crag,  together  with  the 
remains  of  sharks,  and  bones  of  four  species  of  cetaceans, 
or  whale-like  animals. 

It  is  a  remarkable  fact,  that  all,  or  nearly  all,  the  species 
of  reptiles,  birds,  and  beasts  of  the  tertiary  are  extinct. 
The  elephants  of  that  time  were  mastodons  and  mam- 
moths. The  horses  of  that  period  had  differently- formed 
teeth,  and  some  of  them  differently-shaped  feet.  Fig. 
Fi  47  47  represents  the  tooth  of  the  horse  of  the 
pliocene,  found  at  Suffolk,  England.  The 
oxen  were  generally  larger,  and  their  horns 
and  teeth  differed  from  those  of  the  pres- 
ent time. 

Slowly,  from  age  to  age,  animals  appear  to 
have  been  modified,  changing  in  their  struc- 
ture as  the  conditions  of  existence  changed 
around  them.  Those  animals  with  which 
W3  are  familiar  are  but  a  few  of  a  host 
fosses,  innumerable  belonging  to  that  grand  life- 
procession  that  has  marched  through  the  ages.  They 
are  like  islands  in  the  ocean, —  solitary  representatives 
of  perished  multitudes  ;  fragments,  time-worn  as  those 
are  wave-worn ;  in  their  turn  to  disappear,  and  be  suc- 
ceeded by  others  arising  slowly  and  imperceptibly  into 
being. 

While  the  mastodon  and  mammoth  were  flourishing 
in  North  America,  Europe,  and  Asia,  animals  equalling 
them  in  bulk,  though  differing  widely  in  organization, 
existed  in  South  America. 


LECTURES  ON  GEOLOGY.  235 

During  a  dry  season,  a  countryman  hunting  for  cattle 
discovered  on  the  banks  of  the  River  Salado,  south  of 
Buenos  Ayres,  what  appeared  to  be  the  trunk  of  a  tree. 
Throwing  his  lasso  over  it,  with  the  aid  of  his  brother 
Guachos  he  dragged  it  on  to  the  bank.  It  proved  to  be 
an  enormous  bone,  five  feet  in  diameter,  —  the  pelvis  of 
a  megatJierium,  or  monstrous  beast,  as  it  has  been  very 
properly  named.  Other  bones  were  brought  up  at  the 
same  time,  and  among  them  several  vertebrge.  "  To  the 
Guachos,  the  pelvis  luckily  appeared  to  be  useless  :  turn 
it  which  way  they  would,  they  all  agreed  that  it  did  not 
make  half  so  comfortable  a  seat  as  a  bullock's  head,  the 
arm-chair  of  the  pampas."  Some  time  after,  the  bones 
were  sent  as  curiosities  to  the  owner  of  the  land  on 
which  they  were  found :  and  here  Sir  Woodbine  Parish 
discovered  them,  dug  out  many  others,  and  had  them 
conveyed  to  England ;  and  it  is  from  them  that  the 
casts  of  the  megatherium  have  been  made  which  are 
now  in  Boston,  Cambridge,  Arnherst,  and  other  localities. 

Its  length  was  eighteen  feet ;  its  height  at  the  with- 
ers, seven  feet ;  its  pelvis,  —  the  largest  bone  ever  found 
belonging  to  a  land-animal,  —  five  feet  broad;  its  fore- 
foot was  a  yard  long,  and  twelve  inches  wide  ;  its  toes 
terminated  by  large  and  powerful  claws  of  great  length; 
its  thigh-bone  was  nearly  three  times  as  broad  as  that  of 
the  largest  elephant,  its  circumference  at  the  largest 
part  being  three  feet  two  inches.  When  clothed  with 
flefjh,  the  tail  must  have  been  more  than  six  feet  around. 

At  first  sight,  this  seems  to  be  one  of  the  most  mon- 
strous, clumsy,  and  ill-formed  creatures  that  ever  existed  ; 
and  yet,  when  its  structure  is  fully  understood,  we  see 
use,  harmony,  and  perfect  adaptability,  everywhere.  Let 
us  first  examine  its  teeth,  that  we  may  learn  the  kind 


236          .   LECTURES  ON  GEOLOGY. 

of  food  on  which  so  large  *an  animal  subsisted.  It  did  not 
live  on  flesh :  the  teeth  are  broad,  for  grinding  and  chew- 
ing ;  not  sharp,  for  cutting.  It  lived,  then,  on  vegetable 
food  ;  but  what  kind  ?  Not  on  grass  ;  for  it  has  no  front 
teeth,  and  on  a  prairie  it  would  have  starved  to  death. 
Not  on  bushes ;  for  such  a  monster  as  this  would  have 
required  half  an  acre  of  them  for  a  breakfast,  and  it  was 
too  large  and  clumsy  to  travel  fast  or  far.  What  then? 
It  must  have  subsisted  on  trees ;  and,  regarding  this  as 
its  diet,  how  appropriate  the  whole  organization  appears! 
The  pampas,  now  covered  with  grass,  were  at  that-  time 
clad  with  immense  forests;  and  rapid  locomotion  was 
altogether  unnecessary  to  the  animal  that  fed  upon  their 
trees.  Such  an  animal  could  not  climb  them,  and  hang 
suspended  from  the  branches,  as  the  living  sloth  of  South 
America  does,  which  it  most  nearly  resembles  in  struc- 
ture :  but  this  was  unnecessary ;  for  here  was  strength 
that  could  bring  the  branches  and  trees  to  it.  Sitting  on 
its  massive  hind-legs,  supported  by  its  powerful  tail, 
forming  a  secure  tripod,  it  reaches  up  to  the  branches, 
and,  laying  hold  of  them  with  its  long  fore-arms  and 
strong  claws,  brings  them  within  reach  of  its  head :  this 
head  is  so  strong  and  substantial,  and  contains  so  many 
holes  for  the  passage  of  nerves  and  blood-vessels,  that 
it  doubtless  supported  a  proboscis,  probably  flat.  With- 
out stirring  from  its  position,  then,  the  megatherium  could 
pull  down  branches  or  young  trees,  so  as  to  be  reached 
by  the  head,  and  ground  by  the  teeth  j  distant  ones 
could  be  reached  by  the  proboscis,  so  that  its  ponderous 
body  need  not  be  moved  from  its  position ;  and,  even 
when  the  proboscis  could  not  reach  a  far-off  limb,  it  would 
seem,  from  the  shape  of  the  vertebras  of  the  neck,  which 
fit  into  each  other  like  one  cup  of  a  set  into  another^ 


LECTURES  ON  GEOLOGY.  237 

that  the  neck  could  be  elongated,  and  the  tree  stripped, 
before  it  became  necessary  to  move. 

The  remains  of  the  megatherium  have  been  found  in 
all  parts  of  the  pampas  for  a  distance  of  eight  hundred 
miles.  The  carcasses  of  this  and  of  other  animals  were 
floated  down  the  streams,  and  sank  in  their  muddy  beds, 
and  have  thus  been  preserved. 

With  the  megatherium  have  been  found  the  bones  of 
another  gigantic  sloth,  —  the  mylodon,  or  "  mill-tooth," 
as  its  name  signifies.  The  length  of  the  skeleton  is 
eleven  feet,  including  the  tail.  It  appears  to  resemble 
the  sloth  more  closely  than  does  the  megatherium. 

Sometimes  it  appears  that  trees  fell  upon  these  ani- 
mals, and  injured  them.  One  skeleton  of  a  mylodon 
was  found  with  the  outer  part  of  the  skull  broken  in 
two  places,  one  of  which  was  entirely  and  the  other 
partially  healed.  Both  the  megatherium  and  mylodon 
had  skulls  with  outer  and  inner  plates,  separated  by  an 
unusual  thickness  of  air-cells,  so  that  the  outer  one  might 
be  broken,  and  the  animal  still  live  and  recover. 

Two  other  large  sloths  existed  at  the  same  time,  in  the 
same  locality,  —  the  megalonyx  (megale,  "  great ;  "  onux, 
"  claw  ")  and  the  scelidotherium  (scelidos,  the  "  thigh ;  " 
therion,  "  beast "),  so  named  from  the  great  breadth 
of  its  thigh-bone.  Remains  of  species  of  the  mylodon 
and  megalonyx  have  been  found  in  North  America, 
though  they  are  most  abundant  in  South  America;  and 
remains  of  the  mastodon  have  been  found  in  South 
America,  though  less  abundantly  than  in  North  America. 

There  is  a  remarkable  correspondence  between  the 
extinct  fossil  mammals  of  recent  tertiary  deposits  and 
existing  mammals  in  the  same  countries.  In  that  coun- 
try alone  in  which  the  sloth  is  found  have  fossil  sloths 


238  LECTURES  ON  GEOLOGY. 

been  discovered.  Europe,  Asia,  and  Africa  have  fur- 
nished  no  fossil  animal  resembling  the  sloth,  armadillo, 
or  platyrhine  monkey ;  that  is,  a  monkey  with  a  broad 
division  between  the  nostrils  :  but  in  South  America, 
where  alone  sloths  and  armadilloes  exist  to-day,  we  find 
their  gigantic  predecessors ;  and  all  the  fossil  monkeys 
are  platyrhine,  as  are  all  the  living  ones.  One  of  the 
extinct  armadilloes  is  called  the  glyptodon(FigA8)  (glup- 

Fig.  48. 


Glyptodoa  clavipoe. 

ton,  "  sculptured ;  "  odous,  "  tooth  "),  from  its  molar  teeth 
being  marked  on  the  sides  with  grooves.  It  was  an 
animal  with  a  shell  something  like  a  turtle,  and  formed 
of  hexagonal  plates.  It  measured  eleven  feet,  following 
the  curve  of  the  back ;  and  its  armor  was  six  feet  eight 
inches  in  length,  and  nine  feet  across.  It  has  been 
estimated  that  this  carapace,  or  body-armor,  weighed 
more  than  four  thousand  pounds.  The  structure  of  the 
legs  and  feet  was  well  adapted  to  support  this  enor- 
mous weight ;  and  at  the  same  time  the  hind  ones  were 
allowed  such  free  motion  as  was  necessary  in  digging 
and  scratching. 

"  Not  a  relic,"  says  Owen,  "  of  an  elephant,  a  rhinoce- 
ros, a  hippopotamus,  a  bison,  or  a  hyena,  has  yet  been 


LECTURES  ON  GEOLOGY.  239 

detected  in  the  caves,  or  more  recent  tertiary  deposits, 
of  South  America.  Not  a  single  animal  belonging  to 
these  genera  is  found  living  on  that  continent  to-day ; 
but  in  the  Old  World,  where  they  do  exist,  we  find  the 
fossil  remains  of  their  predecessors." 

The  Australian  tertiary  deposits  have  in  like  manner 
yielded  large  extinct  mammals  resembling  the  living 
forms  of  that  country.  All  the  existing  indigenous 
mammals  of  that  country  are  marsupial,  except  the 
dingo,  or  "  Australian  dog."  The  fossil  mammals  which 
are  found  in  caves  and  recent  deposits  are  exclusively 
those  of  marsupials  ;  though  the  species  differ  from  exist- 
ing ones,  and  the  animals  are  generally  much  larger. 

The  living  wombats,  phalangers,  potoroos,  and  kan- 
garoos were  preceded  by  extinct  species  of  the  same 
genera ;  some  of  the  kangaroos  being  of  great  size. 
One  of  these  gigantic  kangaroos,  that  must  have  nearly 
equalled  the  hippopotamus  in  size,  has  been  named,  by 
Owen,  diprotodon  (animal  having  two  front  teeth).  The 
skull,  which  is  now  in  the  British  Museum,  measures 
three  feet  in  length.  The  hind  limbs  were  much 
shorter  and  stronger,  and  the  front  limbs  were  longer 
and  larger,  than  those  of  the  living  kangaroo.  The 
skull  (Fig.  49),  with  part  of  the  skeleton,  was  discovered 
in  a  pliocene  deposit  on  the  Plains  of  Darling  Downs, 
Australia. 

In  the  same  formation  have  been  found  the  remains 
of  a  carnivorous  marsupial  rivalling  the  lion  in  size. 
One  extinct  wombat  was  as  large  as  a  tiger.  Australia 
seems  to  have  become  less  favorable  for  monstrous  mar- 
supials ;  and  they  were  eventually  succeeded  by  the 
smaller  and  feebler  specimens  that  abound  there  at  the 
present  time. 


240 


LECTURES    ON   GEOLOGY. 


When  New  Zealand  was'first  discovered,  no  ma*  imals 
were  found  upon  it,  with  the-exception  of  a  rat;  r-.ut  it 
contained  many  birds,  —  the  most  remarkable,  a  small 

Fig.  49. 


struthious  bird,  that  is,  a  bird  of  the  ostrich  family, 
called  the  apteryx  (wingless),  on  account  of  its  very 
small  rudimental  wings.  In  a  specimen  whose  body 


LECTURES  ON  GEOLOGY.  241 

measured  nineteen  inches,  the  wings,  stripped  of  the 
feathers,  were  only  an  inch  and  a  half  long  ;  ending  in 
a  hard,  horny  claw  three  inches  long.  Several  species 
of  birds  similar  to  the  apteryx  formerly  existed  in  New 
Zealand,  ranging  in  height  from  three  to  ten  feet.  "  A 
small  portion  of  a  bone/7  says  Mrs.  Somerville,  "  which 
from  its  dimensions  appeared  to  belong  rather  to  a 
quadruped  of  the  size  of  an  ox  than  to  a  bird,  was  sub- 
mitted to  Mr.  Owen.  He  boldly  pronounced  it,  from  its 
structure,  to  belong  to  a  bird  of  the  ostrich  kind,  —  a 
decision  that  was  soon  abundantly  confirmed  by  the  dis- 
covery, not  only  of  the  bones  of  the  bird,  but  of  its 
eggs."  This  bird  has  been  called  the  dinornis  (huge 
bird) ;  and  well  it  may.  In  one  specimen,  the  leg-bone 
measured  upwards  of  a  yard  in  length;  and,  in  an- 
other, the  toe-bones  almost  rival  those  of  the  elephant. 
Several  species  of  the  dinornis  have  been  found  j  and 
large  wingless  birds  appear  to  have  abounded  in  the 
large  islands  of  New  Zealand  at  no  very  distant  period. 
The  bones  have  been  found  well  preserved,  and  in  some 
cases  marked  by  edged  tools,  and  mixed  with  human 
bones  in  the  ash-heaps  of  ancient  feasts :  so  that  the 
extinction  of  these  birds  may  be  fairly  attributed  to 
savage  man,  who  found  them  good  eating,  and  easy  to 
kill,  as  they  could  not  fly ;  while  man  was  not  sufficient- 
ly civilized  to  domesticate  and  thus  perpetuate  them. 

In  Madagascar,  portions  of  a  very  large  bird,  the 
epiornis  (tall  bird),  have  been  discovered,  and  entire 
eggs  measuring  from  thirteen  to  fourteen  inches  in 
diameter.  One  of  these  eggs,  it  is  computed,  would 
contain  six  ostrich  eggs,  or  one  hundred  and  forty -eight 
hen's  eggs. 

The  ostrich  family  is  at  present  represented  in  Aus« 

16 


242  LECTURES  ON  GEOLOGY. 

tralia  by  the  emu  ;  in  the  islands  of  the  Indian  archipel- 
ago, by  the  cassowary,  —  next  to  the  ostrich,  the  largest 
of  living  birds ;  in  Africa,  by  the  ostrich,  which  ranges 
from  Barbary  to  the  Cape  of  Good  Hope,  its  wide 
and  uninhabitable  deserts  affording  it  security ;  in 
America,  by  the  rhea,  which  is  found  from  Bolivia  to 
Paraguay  ;  in  New  Zealand,  by  three  species  of  apteryx. 
No  bird  of  this  family  is  found  either  on  the  continent 
of  Europe  or  Asia,  probably  on  account  of  its  destruc- 
tion by  man,  as  the  early  Dutch  navigators  destroyed 
the  dodo,  once  so  abundant  in  the  Mauritius,  and  as  the 
solitaire,  another  wingless  bird,  has  become  extinct  in 
the  Island  of  Rodriguez  and  Bourbon,  where  it  once 
existed  in  great  numbers. 

In  the  pliocene  deposits  of  Montpellier,  France,  re- 
mains of  a  monkey  occur ;  and  in  brick  earth  of  this  age, 
in  Essex,  England,  a  fossil  jaw  and  tooth  of  the  macacus, 
or  bonnet-ape,  have  been  found.  Many  extinct  species 
of  monkeys  were  discovered  by  Dr.  Lund  in  South 
America,  —  all  of  them  platyrhine,  but  much  larger  than 
living  ones,  many  of  them  twice  as  large. 


LECTURE   V. 


As  our  planet  never  twice  occupies  the  same  point  in 
space  as  it  journeys  round  the  sun,  so  it  has  never 
twice  occupied  the  same  position  in  its  progressive 
geologic  movement,  nor  been  twice  in  the  same  con- 
dition, from  its  nebulous  birth  to  the  present  time.  Its 
course  has  been  progressive ;  yet  its  pathway  has  not 
been  perfectly  straight,  nor  the  rate  of  its  march  in- 
variably uniform.  As,  in  the  advancing  spring-time, 
we  are  checked  in  our  anticipations  of  fine  weather  by 
bitter  blasts  as  cold  as  winter's  breath,  so  has  it  been 
in  the  progress  of  the  world.  There  have  been  times 
when  it  seemed  to  be  marching  backward  rather  than 
forward  ;  yet  out  of  all,  as  the  year  advances  to  smiling 
May,  the  world  has  marched  on  to  a  brighter  day. 


GLACIAL  PERIOD. 

The  next  page  in  the  world's  history  brings  us  to 
one  of  those  backward-looking  times  when  a  spectator 
might  have  justly  despaired  of  the  world's  future.  This 
period  is  known  as  the  drift,  or  glacial  period ;  and  is 
marked  by  beds  of  sand,  gravel,  clay,  and  bowlders  from 
the  size  of  a  man's  head  to  that  of  a  meeting-house. 
There  is  one  in  Whittingham,  Mass.,  whose  length  is 

243 


244  LECTURES   ON  GEOLOGY. 

forty  feet,  its  horizontal  circumference  a  hundred  and 
twenty-five  feet,  and  its  estimated  weight  three  thou- 
sand four  hundred  tons.  I  saw  one  in  Maine,  east  of 
Bangor,  that  was  twenty-three  feet  high,  and  seventy 
feet  round,  which,  from  its  position  and  appearance, 
must  have  travelled  a  considerable  distance.  These  pe- 
culiar beds  and  rocks,  lying  near  the  surface  or  on  it, 
have  attracted  attention  from  the  earliest  times.  Whence 
came  they  ?  The  answer  to  this  question  seemed  at  first 
to  be  extremely  easy.  Men  supposed  they  saw  in  them 
evidences  of  a  universal  flood,  the  waters  of  which, 
sweeping  over  the  world,  heaped  up  these  various  beds, 
and  transported  the  bowlders.  With  our  increased 
knowledge,  it  is  impossible  to  accept  such  a  theory  of 
their  origin.  Drift-beds  or  bowlders  are  not  found  farther 
south  than  about  the  latitude  of  39°,  or  the  line  of  Wash- 
ington, Cincinnati,  St.  Louis,  and  Kansas  City,  except 
in  high-mountain  regions.  In  Tennessee  and  Alabama, 
there  are  no  drift-beds  or  bowlders ;  neither  are  there 
any  in  Louisiana  an(J  Texas :  and  it  is  not  until  we  go 
as  far  south  of  the  equator  as  we  find  these  beds  north 
of  the  equator  that  we  discover  similar  deposits.  A 
universal  deluge  would  make  beds  as  universal ;  though 
then  they  would  differ  very  widely  from  drift-beds :  but 
the  fact  that  these  are  confined  to  certain  districts  dis- 
proves the  early  and  common  theory  of  their  origin. 
In  fact,  there  are  no  geologists,  in  the  proper  sense  of 
that  term,  who  believe  that  there  ever  was  a  time,  since 
man  became  an  inhabitant  of  the  globe,  when  it  was 
covered  with  water  to  the  tops  of  the  highest  mountains. 
It  is  simply  impossible.  There  is  not  water  enough 
about  the  planet  to  do  it ;  and  all  the  animals  now  living 
could  never  have  been  preserved  by  man. 


LECTURES  ON  GEOLOGY.  245 

On  this  subject,  the  Rev.  Dr.  Pye  Smith  has  the  fol- 
lowing sensible  remarks :  "  All  land-animals  having  their 
geographical  regions,  to  which  their  constitutional  na- 
tures are  congenial,  —  many  of  them  being  unable  to  live 
in  any  other  situation,  —  we  cannot  represent  to  our- 
selves the  idea  of  their  being  brought  into  one  small 
spot  from  the  polar  regions,  the  torrid  zone,  and  all  the 
other  climates  of  Asia,  Africa,  Europe,  and  America, 
Australia,  and  the  thousand  of  islands,  their  preserva- 
tion and  provision,  and  the  final  disposal  of  them,  with- 
out bringing  up  the  idea  of  miracles  more  stupendous 
than  any  that  are  recorded  in  Scripture.  The  great 
decisive  miracle  of  Christianity,  the  resurrection  of  the 
Lord  Jesus,  sinks  down  before  it." 

Hugh  Miller  shows  us  that  no  such  deluge  has  taken 
place  since  the  tertiary  period.  "  In  various  parts  of 
the  world,  such  as  Auvergne  in  Central  France,  and 
along  the  flanks  of  JEtna,  there  are  cones  of  long- 
extinct  or  long-slumbering  volcanoes,  which,  though  at 
least  triple  the  antiquity  of  the  Noachian  deluge,  and 
though  composed  of  the  ordinary  incoherent  materials, 
exhibit  no  marks  of  de'nudation." 

All  floods  since  the  Silurian  period  must,  in  the  nature 
of  things,  have  been  partial  •  and  of  these  there  must 
have  been  multitudes,  many  of  them  since  man  has 
existed.  In  consequence,  nearly  ail  nations  having  a 
written  or  traditional  history  give  us  some  account  of 
a  flood  or  floods.  The  inhabitants  of  Otaheite  relate 
that  their  island  was  destroyed  by  the  sea,  and  but  one 
man  and  woman  were  saved.  The  Greeks  had  a  tradi* 
y  thus  set  in  poetry  by  Ovid  :  — 

"  Impetuous  rain  descends : 
Nor  from  his  patrimonial  heaven  alone 
Is  Jove  content  to  pour  his  vengeance  down ; 


246  LECTURES  ON  GEOLOGY. 

But  from  his  brother  of  tke  seas  he  craves 

To  help  him  with  auxiliary  waves. 

Then  with  his  mace  the  monarch  struck  the  ground : 

With  inward  trembling,  Earth  received  the  wound ; 

And  rising  streams  a  ready  passage  found. 

Now  earth  and  seas  are  in  confusion  lost,  — 

A  world  of  Avaters,  and  without  a  coast. 

A  mountain  of  tremendous  height  there  stands 

Betwixt  the  Athenian  and  Boeotian  lands  : 

Parnassus  is  its  name,  whose  forky  rise 

Mounts  through  the  clouds,  and  mates  the  lofty  skies. 

High  on  the  summit  of  this  dubious  cliff, 

Deucalion,  wafting,  moored  his  little  skiff: 

He  with  his  wife  were  only  left  behind 

Of  perished  man,  —  they  twain  of  human  kind. 

The  most  upright  of  mortal  men  was  he ; 

The  most  serene  and  holy  woman  she." 

When  they  came  to  land,  the  question  arose  in  the 
minds  of  this  worthy  couple,  "  How  can  the  world  be 
repeopled?"  seeing  that  they  were  too  old  to  expect 
progeny  of  their  own.  Seeking  counsel  from  the  gods, 
Deucalion  was  advised  to  throw  the  bones  of  his  mother 
over  his  head.  This  he  understood  to  mean  stones,  — 
the  bones  of  our  mother-earth.  On  doing  so,  to  his 
great  astonishment  and  delight  they  were  changed  into 
men.  The  old  lady's  were,  of  course,  transformed  into 
women ;  and  thus  the  world  became  inhabited  as  of  old. 

These  various  traditions,  doubtless,  had  their  rise  in 
various  local  floods.  The  bursting  of  lake-barriers  ; 
irruptions  of  the  sea,  caused  by  a  country's  sinking 
below  its  level;  long-continued  rains;  upheavings  of 
the  sea-bottom  by  earthquakes, — these  and  other  causes 
have  laid  large  tracts  of  inhabited  land  under  water,  and 
swept  off  great  numbers  of  human  beings ;  the  survi« 
vors,  owing  to  their  ignorance  of  the  earth's  size, 


LECTURES,  ON  GEOLOGY.  247 

supposing  the  world  to  be  destroyed.  But  the  deposits 
formed  by  such  floods  must  have  been  small,  and  they 
give  us  no  clew  to  the  origin  of  the  glacial  beds. 

There  is  one  appearance  connected  with  these  beds 
that  may  lead  us  to  a  rational  theory  of  their  origin.  On 
digging  below  them,  down  to  what  miners  call  the  bed 
rock,  we  find  this  rock  to  be  covered  with  parallel 
scratches,  or  furrows,  sometimes  called  stride  (from 
scratches  as  fine  as  the  point  of  a  pin  could  make  to  large 
furrows  a  foot  broad  and  two  or  three  inches  deep),  or 
else  they  are  smooth  and  polished.  Such  appearances 
are  very  common  in  the  neighborhood  of  Boston,  at  Rox- 
bury,  Dover,  and  Dorchester:  they  may  be  observed  in 
the  cuttings  on  all  the  railroad  lines  of  Massachusetts ; 
in  all  the  mountain-regions  of  New  England ;  every- 
where in  Canada  ;  on  the  shores  of  Lakes  Ontario,  Erie, 
and  Superior,  —  passing,  in  some  cases,  below  the  water- 
level,  especially  in  Superior.  I  have  seen  them  on  the 
sandstones  of  the  Western  Reserve,  in  Ohio  ;  on  the  lime- 
stone at  Dayton,  in  the  same  State  ;  in  the  bed  of  a  stream 
near  the  Kansas  River;  and  on  the  Rocky  Mountains 
above  Empire  City,  in  Colorado,  and  on  the  Parahlamoosh 
Range  west  of  the  Middle  Park,  at  a  height  of  more  than 
twelve  thousand  feet  above  the  sea-level. 

What  agent  could  do  such  work  as  this?  When  we 
have  discovered  it,  we  probably  have  a  clew  to  the 
agent  concerned  in  making  the  drift-deposits ;  for  where 
we  find  the  one,  we  find  the  other.  The  rocks  found  in 
the  drift  are  also  scratched  or  polished.  These  scratches 
may  be  observed  on  the  sides  of  bowlders  all  over  New 
England,  but  are  most  easily  seen  on  fragments  of  lime- 
stone in  Western  drift-deposits.  We  know  of  but  one 
t  ing  that  could  do  this ;  and  that  is  ice.  In  fact,  ice  is 


248  LECTURES  ON  GEOLOGY. 

engaged  in  doing  just  suc*h  work  at  the  present  time 
At  the  equator,  snow  does  not  melt  that  falls  on  moun- 
tains which  are  more  than  sixteen  thousand  feet  above 
the  sea-level :  three  miles  above  the  hottest  of  summer 
weather  is  winter ;  and,  in  the  temperate  zone,  the  dis- 
tance is  much  less.  In  the  Swiss  Alps,  the  snow  does 
not  melt  at  a  height  of  nine  thousand  feet,  but,  as  it 
falls,  packs  into  ice,  which  accumulates  till  it  forms 
masses,  which  move  slowly  down  the  side  of  the  mountain 
in  the  form  of  rivers  of  ice.  There  are  fifteen  hundred 
square  miles  of  ice  in  the  Alpine  range,  from  eighty  to 
six  hundred  feet  thick.  These  rivers  of  ice,  or  glaciers, 
move  at  various  rates,  according  to  the  nature  of  the 
ground  over  which  they  pass,  and  the  condition  of  the 
weather :  from  eight  to  twelve  inches  a  day  is  an  ordi- 
nary rate  of  advance.  Some  of  the  glaciers  of  the  Alps 
are  as  much  as  twenty  miles  long,  in  places  a  mile  wide, 
and  have  a  thickness  of  many  hundred  feet.  As  these 
immense  bodies  of  ice  slowly  but  irresistibly  move  down 
the  mountain-side,  they  break  off  masses  of  the  rock 
over  which  they  pass ;  and  these  become  embedded  in 
the  bottom,  and  act  as  so  many  groovers,  scoring  the 
rocks  over  which  they  pass  in  parallel  lines ;  while  that 
ice  which  contains  none  of  these,  acts  as  a  polisher  of  the 
rocky  surface  beneath.  Thus  Mr.  Charles  Martins  says, 
"  If  we  penetrate  between  the  soil  and  the  bottom  of  the 
glacier,  taking  advantage  of  the  icy  caverns  which  some- 
times open  at  its  edge  or  extremities,  we  creep  over  a 
bed  of  pebbles  arid  fine  sand.  If  we  raise  this  bed,  we 
find  the  rock  beneath  levelled,  polished,  ground  down  by 
friction,  and  covered  with  rectilinear  stripes,  resembling 
sometimes  a  small  furrow,  more  frequently  deep  scratches, 
perfectly  straight,  as  if  they  had  been  engraved  by  the 


LECTURES  ON  GEOLOGY.  249 

aid  of  a  burin,  or  even  a  very  fine  needle.  If  we  exam- 
ine the  rocks  on  the  side  of  a  glacier,  we  find  the 
same  stripes  engraved  on  them  where  they  have  been 
in  contact  with  the  congealed  mass."  Just  such  appear- 
ances I  have  seen  in  a  thousand  places  over  the  Northern 
States  and  British  Provinces,  from  Cape  Breton  to  beyond 
the  Rocky  Mountains;  and  have  no  doubt  they  were 
made  in  a  somewhat  similar  manner. 

Where  the  temperature  of  a  country  is  so  low  that 
snow  cannot  melt,  the  whole  face  of  it  becomes  covered 
with  snow,  which  consolidates  into  ice,  forming  one 
grand  mass ;  and  this  moves  toward  the  sea  (the  land 
sloping  in  that  direction),  until,  reaching  it,  it  breaks  off 
in  immense  bodies,  which  go  floating  off  as  icebergs, 
carrying  frequently  rocks  upon  their  surface,  which,  when 
they  melt,  are  strewed  on  the  floor  of  the  ocean.  This 
is  the  case  with  Western  Greenland,  as  described  by 
Dr.  Rink,  quoted  by  Lyell. 

"  In  that  country,  the  land  may  be  divided  into  two 
regions,  —  the  inland  and  the  outskirts.  The  inland, 
which  is  eight  hundred  miles  from  west  to  east,  and  of 
much  greater  length  from  north  to  south,  is  a  vast 
unknown  continent,  buried  under  one  continuous  and 
colossal  mass  of  permanent  ice,  which  is  always  moving 
seaward ;  but  a  small  proportion  only  of  it  in  an  east- 
erly direction,  since  nearly  the  whole  descends  towards 
Baffin's  Bay."  On  reaching  the  coast,  it  presents  a  per- 
pendicular wall  of  ice  two  thousand  feet  high,  and  slopes 
gradually  towards  the  interior,  to  unknown  heights,  as 
far  as  the  eye  can  reach. 

"  Although  all  the  ice  is  moving  seaward,  the  greatest 
quantity  is  discharged  at  the  heads  of  certain  large 
filths,  usually  about  four  miles  wide.  Through  these 


250  LECTURES  ON  GEOLOGY. 

the  ice  is  now  protruded  in  .huge  blocks,  several  milea 
wide,  and  from  one  thousand  to  one  thousand  five  hun- 
dred 'feet  in  thickness.  When  these  masses  reach  th<? 
friths,  they  do  not  melt  or  break  up  into  fragments,  but 
continue  their  course  in  a  solid  form  under  the  salt 
water,  grating  along  the  rocky  bottom,  which  they  must 
polish  and  score,  at  depths  of  hundreds,  and  even  more 
than  a  thousand  feet.  At  length,  when  there  is  water 
enough  to  float  them,  huge  portions,  having  broken  off, 
fill  Baffin's  Bay  with  icebergs  of  a  size  exceeding  any 
which  could  be  produced  by  ordinary  valley  glaciers. 
Stones,  sand,  and  mud  are  sometimes  included  in  these 
bergs  which  float  down  Baffin's  Bay." 

There  is  good  reason  for  believing  that  North  America 
during  the  drift  period  was  in  a  similar  condition.  An 
immense  sheet  of  ice,  in  places  thousands  of  feet  in 
thickness,  covered  Canada,  the  British  Provinces,  near- 
ly the  whole  of  New  England,  and  a  large  portion 
of  the  United  States  directly  west ;  this  body  of  ice 
moving  toward  the  ocean  in  the  most  direct  line  that 
the  elevations  of  the  land  would  allow.  Its  general 
direction  was  toward  the  south,  where  it  could  melt,  and 
room  be  found  for  the  accumulating  mass;  transporting 
masses  of  rock,  in  some  cases,  for  hundreds  of  miles. 
Bowlders  of  granite  in  Central  Ohio  and  Indiana  have 
been  carried  from  Canada.  I  have  seen  a  block  of  jasper 
conglomerate  at  Grand  Rapids,  in  Michigan,  and  others 
near  Delphi,  in  Indiana,  that  had  been  transported  from 
the  northern  shore  of  Lake  Superior.  The  northern 
shores  of  Long  Island  are  strewn  with  bowlders  of  red 
sandstone  and  granite  from  Connecticut.  Over  thou- 
sands cf  square  miles  lay  the  great  ice-field,  rising  in 
terrace  beyond  terrace  to  the  north,  slowly  moving  to 


LECTURES  ON  GEOLOGY.  251 

the  south.  Like  an  enormous  rasp,  or  file,  it  rounded  the 
mountains  on  its  march ;  filled  up,  by  the  detritus  worn 
from  the  rocks,  enormous  cavities ;  and,  on  reaching  the 
sea,  pushed  far  into  its  waters,  and  floated  off  in  icebergs 
innumerable,  which,  melting,  strewed  the  ocean-bottom 
with  sand,  gravel,  and  bowlders. 

I  suppose  any  country  from  which  water  would  flow 
into  the  sea,  if  cold  enough  to  become  covered  with  an 
icy  sheet,  would  have  slope  enough  for  the  ice  to  movo 
to  the  ocean  in  glaciers.  In  some  places,  the  force  has 
been  so  great  as  to  push  the  ice  up  considerable  slopes. 

This  cold  period  appears  to  have  come  on  rapidly. 
Down  dropped  the  dome  of  everlasting  cold :  the  seas 
congealed,  rivers  were  stayed  in  their  course,  the  great 
lakes  covered,  and  buried  deep  as  the  Atlantic  depths, 
life  in  its  various  forms  was  destroyed,  and  Winter 
swayed  his  icy  sceptre  over  a  wide  realm  once  so 
summer-like  and  fair. 

In  Europe,  a  somewhat  similar  condition  of  things 
existed.  All  Switzerland,  and  a  considerable  portion  of 
Spain  and  Italy,  have  been  subjected  to  glacial^  action. 
Even  as  far  south  as  Spain  and  Corsica,  vast  plains  of 
ice  existed.  From  Norway  to  Great  Britain,  an  immense 
glacier  extended,  by  which  large  bowlders  were  trans- 
ported across  the  German  Ocean.  Traces  of  ancient 
glaciers  have  been  discovered  in  all  Northern  Europe, 
Russia,  Prussia,  and  in  the  Carpathian  and  Caucasus 
Mountains.  In  Russia,  bowlders  have  been  identified 
with  ledges  more  than  eight  hundred  miles  to  the  north. 
Scotland  and  Wales  sent  out  glaciers  from  their  icy 
mountains  ;  and  the  ocean  to  the  south  must  have  been 
crowded  with  icebergs. 

It  is  remarkable  that  Southern  Patagonia  and  Terra 


252  LECTURES  ON  GEOLOGY. 

del  Fuego  in  South  America,  and  the  Falkland  Islands 
lying  east  of  Southern  Patagonia,  show  similar  signs 
of  glacial  action;  drift-beds,  bowlders,  and  striated  or 
scratched  rock-surfaces,  being  common.  Drift-deposits 
have  been  traced  as  high  as  41°  south  latitude.  More 
remarkable  is  the  fact,  that  on  the  western  coast  of 
Patagonia,  in  the  latitude  of  47°,  which  corresponds 
with  that  of  Central  France,  a  glacier  exists  even  now> 
and  part  of  it  at  the  sea-level.  Capt.  King  says  its 
length  is  fifteen  miles,  while  it  has  a  breadth  in  one  place 
of  seven  miles.  The  deep  sounds  along  the  coast, 
from  there  south,  are  all  furnished  with  glaciers.  Charles 
Darwin  says,  on  a  still  night,  the  cracking  and  groaning 
of  the  great  moving  masses  may  be  distinctly  heard. 

Let  us  look  at  Nova  Scotia,  New  Brunswick,  and  New 
England,  as  they  once  were,  —  a  continental  desert  of 
snow  and  ice  in  the  interior  of  the  country,  and  the 
ocean  fringed  with  a  gigantic  ice-wall  for  thousands 
of  miles ;  icebergs  high  as  the  proudest  steeple ;  crystal 
islands  floating  off  to  the  south;  birds  in  multitudes 
hovering  over  them  like  clouds.  The  sea  has  fish  in- 
numerable, and  troops  of  walruses  that  feed  upon  them ; 
whales  are  spouting,  and  white  bears  swimming  from  one 
ice-floe  to  another.  Possibly  man,  fur-clad,  armed  with 
a  stone  spear,  killed  the  seal  that  slept  on  the  sea-margin, 
and  even  attacked  the  walrus  and  the  bear.  Icebergs, 
detached  from  the  pushing  glaciers,  float  off  into  the  sea, 
and,  melting,  drop  their  rocky  burdens. 

"Mr.  Scoresby  counted  in  view,  at  one  time,  as  many  as 
five  hundred  icebergs  drifting  along  in  latitude  69°  and 
70°  north ;  these  bergs  rising  above  the  surface  to  a  height 
varying  from  one  to  two  hundred  feet,  and  measuring 
from  a  few  yards  to  a  mile  in  circumference  at  the  water- 


LECTURES  ON  GEOLOGY.  253 

line;  and  as  the  mass  of  ice  below  the  wcier  is  known 
to  be  always  seven  or  eight  times  greater  than  that 
which  appears  above  it;  and  the  whole  is  loaded  with 
fragments  of  rocks,  the  effect  of  the  gradual  melting  of 
such  masses  must  inevitably  be  to  strew  the  bed  of  the 
sea  with  a  vast  quantity  of  gravel  and  erratic  blocks." 
Mr.  Scoresby  calculated  that  some  of  them  carried  one 
hundred  thousand  tons  of  earth  and  stones.  Many  large 
bowlders  now  on  dryland  were  probably  dropped  on  the 
sea-bottom  in  this  way  during  the  drift  period. 

The  snow  at  last  melted ;  the  mighty  mountains  of 
adamantine  ice  dissolved,  and  rivers  rushed  from  their 
bases,  sweeping  away  loose  sediment,  and  changing  its 
appearance  as  first  left  by  the  now  retreating  glaciers. 
Up  sprang  the  grasses  from  the  long-buried  and  ice- 
preserved  seeds ;  and  the  trees  again  put  forth  their 
leaves,  and  their  branches  bowed  to  the  breeze.  The 
long  winter  was  past,  and  a  glorious  spring  came  with 
the  promise  of  a  blooming  summer. 

But  what  could  have  made  it  so  cold  during  this  time? 
Nobody  knows.  Many  theories  have  been  formed  to 
account  for  it ;  but  none  of  them  seems  satisfactory. 
Some  suppose  that  there  are  cold  and  hot  regions  in 
space ;  that  as  the  motion  of  our  planet  around  the  sun 
gives  us  spring,  summer,  fall,  and  winter,  so  the  motion 
of  our  sun  around  a  grand  central  sun  may  produce 
seasons  for  the  solar  system.  The  drift  period,  then,  was 
the  winter :  we  are  living  in  the  spring,  and  may  anti- 
cipate the  summer.  Very  comfortable  doctrine  truly, 
especially  in  cold  weather,  but,  like  some  other  comfor- 
table doctrines,  has  little  or  no  basis.  Astronomers  know 
nothing  of  cold  or  hot  regions  in  space ;  and,  until  some 
facts  are  produced  to  favor  it,  that  theory,  cr  rather 
hypothesis,  may  be  dismissed. 


254  LECTURES  ON  GEOLOGY. 

It  has  been  suggested  bjf  several,  that,  if  the  land  wag 
sufficiently  elevated  above  the  ocean  during  this  period, 
all  the  phenomena  connected  with  it  must  have  taken 
place  ;  and  this,  no  doubt,  is  true.  If  the  European  con- 
tinent^  should  be  elevated  three  thousand  feet,  most  of 
its  surface  would  be  covered  with  a  glacial  sheet,  over- 
laid by  perpetual  snow.  If  the  North-American  conti- 
nent should  be  lifted  up  eight  thousand  feet  above 
its  present  level,  snow  would  fall  upon  its  surface  as 
at  present,  but,  over  a  large  portion  of  that  surface, 
would  fail  to  melt.  In  time,  an  immense  glacier  would 
cover  the  whole  of  the  northern  portion,  extending  as 
far  south  as  the  chain  of  lakes,  and,  slowly  pushing  out 
southward,  would  transport  blocks  from  north  to  south  ; 
round  the  hills  and  mountains  over  which-  it  passed ; 
grind  down  the  sandstone  rocks  to  sand,  and  the  shaly 
and  slaty  rocks  to  clay;  and  produce  ju^t  such  beds  and 
appearances  as  we  are  familiar  with.  But  what  should 
elevate  the  continent  thus,  —  still  more  the  European 
continent  in  a  similar  manner,  and  during  the  same 
period?  It  is  difficult  to  believe  that  elevations  so 
extensive  and  so  great  could  have  taken  place  during 
any  one  period  ;  and  we  are  still  left  in  the  dark  in  refer- 
ence to  the  cause  of  the  intense  cold  of  the  glacial  time. 

It  has  been  suggested  that  the  inclination  of  the 
earth's  axis  to  the  plane  of  its  orbit,  which  is  23°  28', 
and  is  the  cause  of  our  present  seasons,  may  have  been 
so  different  during  the  glacial  period  as  to  make  the 
frigid  zone  coincide  with  those  portions  pf  the  eartli 
where  glacial  action  occurred  during  the  drift  period. 
This  is,  perhaps,  the  most  reasonable  supposition.  Dr. 
Winslow  remarks  in  his  "  Cooling  Globe/'  "  Suddenly 
transplant  Greenland  from  its  present  connection  with 


LECTURES  ON  GEOLOGY.  255 

the  bottom  of  the  Atlantic  to  the  south  of  Australia, 
whi/t  would  be  the  geological  and  the  geographical 
changes  upon  the  surface  of  the  whole  globe  ?  As  small 
as  Greenland  is  in  superficial  extent,  the  earth  would 
instantly  feel  the  disturbance  of  its  equilibrium ;  and  the 
inclination  of  its  axis  to  the  plane  of  its  orbit  would 
become  sensibly  affected.  The  physical  results  and 
changes  in  distribution  of  organic  life  that  would  neces- 
sarily follow  would  be  universal  in  character  and  extent. 
Similar  consequences  would  naturally  follow  the  slow 
elevation  or  submergence  of  continents."  Since  all 
the  planets  the  inclinations  of  whose  axes  are  known 
differ  from  the  earth  in  the  amount  of  their  inclination, 
it  is  not  unreasonable  to  suppose  that  the  earth's  incli- 
nation was  once  different,  and  that  it  has  been  constantly 
changing  to  suit  the  changing  condition  of  its  surface. 
This  would  necessitate  climatal  changes  to  correspond, 
and  may  have  produced  the  phenomena  of  the  drift. 

Geology  is  young  ;  and  there  are  many  problems  yet 
to  be  solved,  and  difficulties  to  be  conquered,  that  our 
children  will  delight  to  grapple  with  and  overcome. 

The  drift-beds  are  interesting  to  us  from  the  fossils 
that  they  contain.  During  the  early  part  of  the  drift 
period,  when  the  icy  covering  began  to  extend  south- 
ward, animals  of  many  kinds,  some  now  extinct,  in- 
habited regions  that  the  ice  subsequently  covered  ;  and 
hence  we  find  in  the  beds  of  that  period  their  remains. 
But  few  have  been  found  in  North  America ;  but  in  Great 
Britain  and  the  continent  of  Europe  they  are  numerous. 
From  them  we  learn,  that,  during  the  drift  period,  two 
species  of  bats  existed  in  Europe,  —  the  great  bat  and  the 
horse-shoe  bat,  both  now  living.  Bears  were  numerous  : 
three  kinds  at  least  have  been  determined.  One  of  theso 


256 


LECTURES   ON  GEOLOGY. 


was  the  common  brown  bear  of  Europe,  a~  second  smaller, 
and  the  third  the  great  cave  bear,  which,  according  to 
Cuvier,  sometimes  attained  the  size  of  a  large  horse  :  its 
remains  are  numerous  in  England,  France,  Belgium,  and 
Germany.  In  one  cave  at  Gaylenreuth,  it  is  said  that 
fragments  of  eight  hundred  of  them  have  been  dis- 
covered. 

A  great  cave  tiger,  twice  as  large  as  the  living 
tiger,  roamed  over  England  and  Europe  ;  and  with  this 
a  smaller  tiger,  a  leopard,  a  wild-cat,  and  other  animals 
of  the  cat  kind. 

In  Great  Britain,  Europe,  and  Asia,  the  remains  of 
a  remarkable  carnivorous  animal,  called  a  macliairodm, 
have  been  discovered.  This  animal  was  about  the  size 
of  a  tiger ;  and  from  the  size  and  shape  of  the  canine 
teeth,  which  resembled  a  sword,  must  have  been  a 
destructive  creature. 

At  the  same  time,  beavers  abounded,  of  much  larger 
size  than  the  North-American  beaver  ;  and  an  animal 
allied  to  it,  but  still  larger,  has  likewise  been  found. 

Fig.  50  represents  the 
skull,  of  a  beaver-like 
animal,  one  -  fifth  the 
natural  size.  It  was 
found  near  Clyde,  N.Y. 
This  species  is  the 
largest  of  the  roden- 
tia  ever  discovered. 
The  mammoth  appears 
to  have  been  very 
abundant.  It  is  sup- 
posed that  upwards  of  two  thousand  grinders  have 
been  dredged  up  by  fishermen  off  the  little  village  of 


Fig.  50. 


Castoroides  Oliioensis, 


LECTURES  ON  GEOLOGY.  257 

Happisburg  in    Norfolk,  England.      The  size  to  which 
they  occasionally  attained  is  indicated  by  Fig.  51,  which 


Fig.  51. 


Elephas  primigenius. 

is  one-fifth  the  natural  size.      The  original,  now  in  the 
Ward  Museum,  Rochester,  weighs  fourteen  pounds. 

But  Northern  Asia  seems  to  have  been  the  home  of 
the  mammoth.  There  is  scarcely  a  river  in  which  their 
remains  have  not  been  found ;  and  even  the  islands  in 
the  icy  sea  north  of  Siberia  abound  with  them.  Bel- 
ling, a  Russian,  who  visited  them,  says  of  one,  "  All  the 
island  nearest  to  the  mainland,  which  is  about  thirty-six 
leagues  in  length,  except  three  or  four  small  rocky 
mountains,  is  a  mixture  of  sand  and  ice  ;  so  that  when 
the  thaw  sets  in,  and  its  banks  begin  to  fall,  many  mam- 
moth bones  are  found.  All  the  isle  is  formed  of  the 
bones  of  this  extraordinary  animal,  of  the  horns  and 
skulls  of  buffaloes  or  an  animal  which  resembles  them, 
and  of  some  rhinoceroses'  horns."  Most  of  the  ivory  used 
by  the  civilized  world  is  obtained  from  the  mammoth 

17 


258  LECTURES  ON  GEOLOGY. 

tusks  of  Siberia.  In  the  year  1844,  sixteen  thousand 
pounds  of  teeth  and  tusks  of  mammoths  were  obtained, 
and  sold  in  St.  Petersburg. 

In  1799,  a  Tungusian  fisherman  observed  in  an  icy 
cliff  at  the  mouth  of  the  Lena  an  odd-shaped  block 
which  attracted  his  attention.  Two  years  afterward,  it 
was  considerably  exposed ;  and  he  saw  the  whole  side 
and  the  tusks  of  a  mammoth.  In  1804,  the  season  being 
warmer  than  usual,  the  body  of  the  mammoth  became 
disengaged  from  the  ice,  and  fell  on  the  beach  ;  when  the 
fisherman  removed  the  tusks,  and  sold  them.  Two  years 
afterward,  Mr.  Adams,  who  was  on  a  mission  from  St. 
Petersburg  to  China,  heard  of  the  discovery,  and  visited 
the  spot.  The  people  of  the  neighborhood  had  cut  off 
the  flesh  to  feed  their  dogs,  and  wild  beasts  had  also 
mangled  it :  the  skeleton,  however,  was  nearly  entire. 
"  The  head  was  covered  with  a  dry  skin ;  one  of  the 
ears,  well  preserved,  was  furnished  with  a  tuft,  or  mane  ; 
the  balls  of  the  eyes  were  distinguishable;  the  brain 
still  occupied  the  cranium,  but  was  dried  up ;  the  top 
of  the  neck  was  furnished  with  a  flowing  mane ;  the 
skin  was  covered  with  tufts  of  black  hairs  and  reddish 
wool.  More  than  thirty  pounds  of  hair  and  wool  were 
collected,  which  the  white  bears  had  taken  from  it,  and 
trampled  in  the  soil.  The  animal  was  a  male :  its  tusks 
were  more  than  nine  feet  long,  and  its  head  and  tusks 
weighed  more  than  four  hundred  pounds."  Mr.  Adams 
repurchased  the  tusks,  carried  the  animal  to  St. 
Petersburg,  and  sold  it  to  the  Emperor  of  Russia  for  six 
thousand  dollars. 

The  mastodon  still  existed.  No  extinct  mammal  with 
which  we  are  acquainted  had  a  wider  range.  Its  re- 
mains have  been  found  on  every  continent,  and  from  the 


LECTURES  ON  GEOLOGY.  259 

tropics  to  the  polar  seas.  Of  the  hippopotamus  there 
were  two  species,  —  one  larger,  and  the  other  smaller, 
than  that  now  inhabiting  the  Nile. 

The  remains  of  a  two-horned  rhinoceros  have  been 
found  in  Europe  and  Asia :  its  body  was  covered  with 
hair,  and  destitute  of  those  rough  scales  seen  on  the  skin 
of  the  African  rhinoceros.  One  of  these,  preserved  in 
frozen  sand,  was  found  on  the  banks  of  the  Viloui,  in 
Siberia,  in  1771  ;  the  very  flesh  still  remaining  on  the 
bones,  and  the  hairy  skin  covering  it.  This  and  the 
mammoth  were  evidently  fitted  for  a  colder  climate  than 
that  in  which  the  living  species  of  the  elephant  and 
rhinoceros  are  now  found ;  though  neither  could  exist 
at  present  where  their  remains  have  been  found,  owing 
to  the  extreme  rigor  of  the  climate.  It  has  been  sug- 
gested, since  the  rivers  run  in  Siberia  from  south  to 
north,. that  their  bodies  may  have  been  floated  many  hun- 
dred miles  from  a  warmer  country  to  the  spot  where  they 
became  embedded  in  ice.  The  bulky  carcass  of  a  mam- 
moth or  rhinoceros  would  float  a  long  way  before  dis- 
integrating by  putrefaction.  This  occurring  in  the 
Lena  towards  winter,  when  there  is  ice  at  its  mouth, 
it  might  be  frozen  in,  and  preserved  for  ages.  This 
explanation  is,  however,  I  think,  inadequate  to  account 
for  the  facts. 

In  the  drift  have  likewise  been  found  two  species 
of  the  horse  (one  the  size  of  the  common  horse,  and 
the  other  that  of  the  zebra),  two  species  of  camels,  a 
gigantic  musk-ox,  a  giraffe,  deer  of  various  kinds,  and 
the  great  Irish  elk. 

The  remains  of  the  great  Irish  elk,  Megaceros  Hiber- 
nicus  (great  horn  of  Ireland),  Fig.  52,  are  found  abun- 
dantly in  peat-bogs  and  marl-pits  in  Ireland,  so  that  it 


260  LECTURES  ON  GEOLOGY. 

is  not  considered  a   curiosity.     It  is  found  also  in  the 
Isle   of  Man,   England,    France,    Germany,   and   Italy. 

Fig.  52. 


Megaceros  Hibernicus. 

Ireland  was,  perhaps,  where  they  lived  most  recently, 
as  their  remains  are  found  there  in  better  preservation, 
and  in  greater  abundance. 

One  perfect  skeleton  was  found  there,  which  is  now 
in  the  museum  of  the  Royal  Dublin  Society.  From  the 
tip  of  one  horn  to  the  tip  of  the  other,  it  measures  twelve 
feet,  less  two  inches  ;  arid  from  the  ground  to  the  highest 
point  of  the  horn,  nearly  ten  feet  and  a  half.  The 
weight  of  the  skull  of  one,  without  the  lower  jaw,  was 
five  pounds  and  a  quarter ;  while  the  same  skull  with 
lower  jaw  and  antlers  was  eighty-seven  pounds. 

Man  probably  existed  coeval  with  this  enormous  deer. 
In  Germany,  there  were  found  in  the  same  drain  several 
urns  and  stone  hatchets,  and  a  head  of  this  extinct  elk. 
In  Ireland,  a  human  body  was  found,  under  eleven  feet 
of  peat,  in  good  preservation,  and  clad  in  garments 
made,  apparently,  of  the  hair  of  this  animal.  There 
exists  a  rib  in  Dublin,  which  had  evidently,  during  the 
lifetime  of  the  animal,  been  pierced  by  some  sharp  in- 
strument, apparently  a  stone  arrow,  as  there  was  such  a 
mark  upon  it  as  that  would  have  made. 


LECTURES  ON  GEOLOGY.  261 

Several  species  of  oxen  were  contemporaneous  with 
the  Irish  elk,  some  of  them  of  gigantic  size.  One,  Bos 
primigenius  (primitive  ox),  the  skull  of  which  is  repre- 
sented by  Fig.  53,  is  said  to  have  existed  in  Switzerland 

Fig.  53. 


Bos  primigenius. 

as  recently  as  the  sixteenth  century.  One  gigantic  ox 
was  nearly  as  large  as  an  elephant. 

But  more  important  than  all  these,  in  the  more  recent 
drift  and  in  caves,  accompanying  extinct  animals,  have 
been  found  the  works  and  the  remains  of  man. 

Considerable  attention  was  turned  to  the  bones  fre- 
quently found  on  the  floors  of  caves,  by  the  publication 
of  a  volume  by  Dr.  Buckland  on  the  Kirkdale  Cave, 
discovered  at  Kirkdale,  in  Yorkshire,  in  1820.  "  The 
bottom  of  the  cave,"  says  the  doctor,  "  on- first  removing 
the  mud,  was  found  to  be  strewed  all  over,  like  a  dog- 
kennel,  from  one  end  to  the  other,  with  hundreds  of 
teeth  and  boner,  or  rather  broken  and  splintered  frag 


262  LECTURES  ON  GEOLOGY. 

merits  of  bones,  of  the  elephant,  bear,  hyena,  rhinoceros, 
and  hippopotamus.  Those  of  the  larger  animals  were 
found  even  in  the  inmost  and  smaller  recesses.  Scarcely 
a  bone  has  escaped  fracture.  On  some  of  the  bones 
marks  may  be  traced,  which,  on  applying  one  to  the 
other,  appear  exactly  to  fit  the  form  of  the  canine  teeth 
of  the  hyenas  found  in  the  cave."  Mr.  Gibson  alone 
collected  more  than  three  hundred  canine  teeth  of  the 
hyena  from  this  cave. 

This  appears  to  have  been  a  den  of  hyenas  for  a  long 
time.  Into  the  woods  they  sallied,  and  dragged  in  the 
carcasses  and  bones  of  large  animals  which  they  found, 
and  small  animals  which  they  overpowered  and  killed ; 
and  in  the  inmost  recesses  of  the  cave  they  lay  and 
munched  them.  Dr.  Buckland  visited  the  Zoological 
Gardens  in  London ;  and,  on  presenting  bones  to  hyenas 
there,  he  noticed  that  the  marks  made  upon  them 
by  their  teeth  resembled  those  found  on  the  bones  dis- 
covered in  the  cave.  Some  of  the  bones  of  the  cave 
hyena  show  that  it  occasionally  attained  the  size  of  a 
Bengal  tiger. 

In  1840,  a  gentleman  of  the  name  of  M'Enery,  resid- 
ing near  Torquay,  in  Devonshire,  England,  found  in  a 
cave  about  a  mile  from  the  town,  called  Kent's  Hole, 
human  bones  and  flint  knives  among  a  great  variety 
of  extinct  species,  —  such  as  the  mammoth,  two-horned 
rhinoceros,  cave  bear,  and  hyena,  all  from  under  a  crust 
of  stalagmite  ;  and  reposing  upon  it  was  the  head  of  a 
wolf.  Dr.  Buckland  visited  the  spot,  and,  on  insufficient 
grounds,  came  to  the  conclusion  that  the  remains  of 
man  and  his  implements  were  not  as  old  as  the  bones 
of  extinct  animals  that  accompanied  them ;  for  Mr. 
Godwin  Austen  declared,  in  1842,  that  he  had  obtained 


LECTURES  ON  GEOLOGY.  263 

from  the  same  cave,  from  undisturbed  loam  or  clay  under 
stalagmite,  works  of  man,  mingled  with  the  remains 
of  extinct  animals  ;  and  that  all  these  must  have  been 
introduced  "  before  the  stalagmite  flooring  had  been 
formed." 

In  1858,  a  new  cave  was  discovered  at  Brixham,  near 
Torquay ;  and  it  was  resolved  to  examine  it  carefully 
and  thoroughly.  The  Royal  Society  defrayed  part  of 
the  expenses ;  and  the  work  was  carried  on  by  the 
direction  of  Mr.  Pengelly,  a  gentleman  of  much  expe- 
perience  in  searching  caves,  and  Mr.  Prestwich  ;  Dr. 
Falconer  taking  an  active  part  in  examining  the  pro- 
ceedings from  time  to  time. 

They  found  first  a  layer  of  stalagmite,  from  one  to 
fifteen  inches  in  thickness,  in  which  some  bones  were 
found.  Below  this  was  loam  or  bone  earth,  from  one 
foot  to  fifteen  feet  in  thickness.  The  floor  of  the  cave 
was  found  to  be  composed  of  gravel,  that  had  a  thick- 
ness of  more  than  twenty  feet.  In  the  bone  earth 
were  found  the  remains  of  the  mammoth,  the  two-horned 
rhinoceros,  the  cave  bear,  cave  hyena,  cave  lion,  and 
reindeer. 

No  human  bones  were  found,  but  a  number  of  flint 
knives,  some  of  them  even  in  the  lowest  gravel ;  but 
well-formed  ones  were  taken  from  the  bone  earth,  and 
one  of  the  most  perfect  at  a  deptli  of  thirteen  feet  in 
the  bone  earth,  close  to  the  left  hind-leg  of  a  cave  bear. 
"  Every  bone,"  says  Lyell,  "  was  in  its  natural  place : 
and  it  appears  evident  "  that  the  bear  lived  after  the 
flint  tools  were  manufactured  ;  or,  in  other  words,  that 
man  in  this  district  preceded  the  cave  bear." 

Long  before  this,  discoveries  of  a  somewhat  similar 
xind  had  been,  made  in  the  river-beds  of  France  by 


264  LECTURES  ON  GEOLOGY. 

M.  Boucher  de  Perthes.  His  first  discoveries  were 
made  at  Abbeville,  on  the  River  Somme,  in  1841,  and 
consisted  of  numerous  flint  implements,  associated  with 
the  remains  of  the  deer,  horse,  mammoth,  rhinoceros, 
elephant,  hyena,  tiger,  and  hippopotamus.  The  imple- 
ments consisted  of  flakes  of  flint,  apparently  intended 
for  knives  or  arrow-heads ;  pointed  implements  from 
four  to  nine  inches  long,  used  for  spear  or  lance  heads  ; 
and  oval  implements,  with  a  cutting  edge  all  round. 

M.  Perthes  published  a  volume  in  1846,  in  which  the 
implements  were  figured,  and  information  given  regard- 
ing their  discovery ;  but,  being  too  far  in  advance  of 
his  contemporaries,  his  book  was  disregarded,  except 
by  a  few  of  his  friends.  A  translation  published  in 
Liverpool  met  with  the  same  fate. 

In  1854,  Dr.  Rigollot,  an  eminent  physician  of  Amiens, 
situated  also  on  the  Somrne,  who  had  been  very  scep- 
tical about  these  discoveries,  was  induced  to  visit 
Abbeville,  where  he  examined  M.  Perthes'  collection ; 
and,  returning  to  Amiens,  soon  discovered  similar  re- 
mains in  the  gravel-pits  near  that  city.  He  obtained, 
from  beds  containing  the  remains  of  "  the  mammoth,  an 
extinct  rhinoceros,  and  other  animals  now  foreign  to 
Europe,  four  hundred  relics,  most  of  them  in  silex, 
and  wrought  with  singular  skill.  They  consisted  of 
hatchets,  poniards,  knives,  triangular  cones,  besides 
perforated  globes,  seemingly  beads  for  necklaces  arid 
bracelets."  Up  to  this  time,  more  than  a  thousand  im- 
plements have  been  found  in  the  Valley  of  the  Somme 
in  ah  area  fifteen  miles  long. 

Notwithstanding  the  evidence  furnished  by  these  dis- 
coveries, considerable  doubt  was  expressed  regarding 
them,  especially  by  the  geologists  of  ijngland.  The 


LECTURES  ON  GEOLOGY.  265 

doubt  was  dispelled,  however,  by  the  visits  of  Messrs. 
Prestwich  and  Lyell  of  England,  and  Gaudry  of  France. 

In  the  report  of  Mr.  Prestwich  to  the  Royal  Society, 
he  says  he  found  the  gravel-beds  capping  a  low  chalk 
hill,  and  not  commanded  by  any  higher  ground.  The 
upper  bed  consists  of  from  ten  to  fifteen  feet  of  brown 
brick  earth,  containing  old  tombs  and  coins,  but  no 
organic  remains.  Under  this  is  a  whitish  marl  and  sand 
with  recent  shells,  and  mammalian  bones  and  teeth, 
whose  thickness  varies  from  two  to  eight  feet.  Lastly, 
there  are  six  to  twelve  feet  of  coarse  subangular  flint 
gravel,  with  some  remains  of  shells  in  sand,  and  teeth 
and  bones  of  the  elephant,  horse,  ox,  and  deer :  with 
these  the  flints  were  found.  Mr.  Prestwitch  was  satis- 
fied, though  he  says  he  undertook  the  examination  full 
of  doubt. 

"  Doubt,  but  examine,"  would  be  an  excellent  motto 
for  other  fellows  besides  fellows  of  the  Royal  Society. 

Lyell,  who  obtained  seventy  of  these  flint  weapons, 
expresses  himself  strongly  in  favor  of  their  great 
antiquity.  Referring  to  the  disappearance  of  the  ele- 
phant, rhinoceros,  and  other  genera  of  quadrupeds  now 
foreign  to  Europe,  he  says  it  "  implies  a  vast  lapse  of 
ages,  separating  the  era  in  which  the  fossil  implements 
were  framed,  and  the  invasion  of  Gaul  by  the  Romans. " 

M.  Gaudry,  a  member  of  the  French  Institute,  accom- 
panied by  three  other  gentlemen,  visited  the  quarry 
at  St.  Acheul  near  Amiens,  and  caused  it  to  be  opened 
for  the  length  of  about  seven  yards.  He  watched  the 
whole  operation,  and  never  left  the  ground  while  the 
work  went  on.  They  found  an  overlying  bed  eleven 
feet  in  thickness,  in  which  nothing  was  found  ;  below 
this  a  flinty  bed,  reposing  on  white  sand,  from  which 


266  LECTURES  ON  GEOLOGY. 

nine  flint  implements  were  obtained.  The  edges  of  the 
flints  were  sharp ;  and  in  the  same  bed,  at  a  little  distance^ 
were  found  remains  of  the  rhinoceros,  hippopotamus, 
and  mammoth. 

Mr.  Lubbock,  in  his  article  on  the  Antiquity  of  Man, 
in  "  The  Natural-history  Review,"  says,  "  He  must  have 
seen  the  Somme  running  at  a  heigl  c  of,  in  round  num- 
bers, one  Irundred  and  fifty  feet  above  its  present  level. 
From  finding  the  hatchets  in  the  gravel  up  to  a  level  of 
a  hundred  feet,  it  is  probable  that  he  dates  back  in 
Northern  France  almost,  if  not  quite,  as  long  as  the 
rivers  themselves.  The  face  of  the  country  must  have 
been  indeed  unlike  what  it  is  now.  Along  the  banks  of 
the  rivers  ranged  a  savage  race  of  hunters  and  fisher- 
men ;  and  in  the  forests  wandered  the  mammoth,  the 
two-horned,  woolly  rhinoceros,  a  species  of  tiger,  the 
musk-ox,  the  reindeer,  and  the  urus." 

Let  us  transport  ourselves  to  those  primitive  times, 
when  these  rude  men  with  their  stone'  weapons  lived  on 
the  banks  of  the  European  rivers,  and  fished  along  the 
coast.  The  seasons  are  fairly  established ;  and  spring 
follows  winter,  and  fall  summer,  as  now ;  though  the  sum- 
mer is  longer  and  warmer  than  we  are  accustomed  to 
see  in  those  countries  at  the  present  time,  and  the 
winters  colder.  The  country  is  covered  with  dense 
forests,  through  which  ramble  might}'  elephants  in  herds, 
with  immense  curved  tusks,  coats  of  long,  shaggy  hair, 
and  flowing  manes.  How  proudly  march  these  aristo- 
crats of  the  elephant  family  !  Shuffling  along  comes  the 
great  cave  bear  from  his  rocky  den,  as  large  as  a  horse : 
fierce,  shaggy,  conscious  of  his  strength,  he  fears  no  ad- 
versary. Crouched  by  a  bubbling  spring  lies  the  cave 
tiger ;  and,  as  the  wild  cattle  come  down  to  drink,  he 


LECTURES   ON   GEOLOGY.  267 

leaps  upon  the  back  of  one,  and  a  terrible  combat  ensues, 
It  is  as  large  as  an  elephant,  and  its  horns  of  enormous 
size ;  and  even  cave  tigers  could  not  always  master  such 
cattle  as  they. 

Are  these  the  highest  forms  of  life  that  the  country 
contains  ?  What  being  is  that  sitting  on  yon  fallen  tree  ? 
His  long  arms  are  in  front  of  his  body,  and  his  hands 
between  his  knees ;  while  his  long,  hairy  legs  are  dan- 
gling down.  His  complexion  is  dark  as  an  Indian's  ;  his 
beard  scanty,  while  his  unkempt  hair  hangs  down  in 
snaky  locks  ;  his  eyebrows  overshadow  his  eyes  ;  so  that, 
with  his  sloping  forehead  and  brutal  countenance,  he 
seems  like  the  caricature  of  a  man,  rather  than  an  actual 
human  being. 

Beneath  the  shade  of  a  spreading  chestnut  we  may 
behold  a  group,  —  one  old  man  with  a  short,  thin  beard, 
and  women  and  children,  lounging  and  lying  upon  the 
ground.  How  dirty  !  What  forbidding  countenances  !  — 
more  like  furies  than  women.  One  young  man  with  a 
stone  axe  is  separating  the  bark  from  a  neighboring 
tree,  to  cover  the  wretched  hut  in  which  they  shelter 
themselves  during  a  storm.  Others,  like  monkeys,  are 
climbing  the  trees,  and  passing  from  branch  to  branch,  as 
they  gather  the  wild  fruit  that  abounds  on  every  side. 
Some  are  catching  fish  in  the  shallows  of  the  river,  and 
yell  with  triumph  as  they  hold  their  captives  by  the 
gills,  dragging  them  to  the  shore.  Their  language  of 
signs,  and  rude,  undistinguishable  sounds,  gives  little 
promise  of  the  polished  tongues  of  Europe. 

Rude  as  this  conception  represents  the  primitive  man, 
facts  warrant  the  assumption  that  the  early  u  stone  men" 
of  Europe  were  even  in  a  more  brutal  condition  than  this. 
Man  is  in  harmony  with  all  other  organized  existences  on 


268  LECTURES  ON  GEOLOGY. 

the  planet ;  and  their  appearance  in  constantly  advancing 
forms,  from  the  Cambrian  period  to  the  present,  shows 
us  the  necessarily  rude  condition  of  the  primitive  man. 
As  the  earliest  known  fish  are  small  and  low  in  organiza- 
tion ;  the  early  reptiles,  of  the  lowest  order  of  reptiles  ;  the 
early  mammals,  undeveloped  marsupials :  so  the  early 
men  were  rude,  brutal,  savage  men,  requiring  ages  for 
their  development  into  civilized  and  enlightened  people. 
"We  are  not  left,  however,  merely  to  this  inference :  facts 
bear  strongest  testimony  to  this  important  fact.  Marcel 
de  Serres  says,  "  The  human  heads  discovered  in  divers 
localities  of  Germany  (in  caves  or  in  ancient  diluvial 
deposits)  have  nothing  in  common  with  those  of  the 
present  inhabitants  of  the  country.  Their  conformation 
is  remarkable  in  that  it  offers  a  considerable  flattening 
of  the  forehead,  similar  to  that  which  exists  among  all 
savages  who  have  adopted  the  custom  of  compressing 
this  part  of  the  head. 

"  Those  found  near  Baden,  in  Austria,  present  strong 
analogies  with  those  of  the  African  or  negro  race  ;  while 
those  from  the  banks  of  the  Rhine  and  Danube  resemble 
the  Caribs,  or  the  ancient  inhabitants  of  Chili  and  Peru. 

"  In  caves  near  Liege  were  found  portions  of  the 
skull  and  other  bones  of  man  along  with  bones  of  an 
extinct  bear,  hyenas,  lions,  &c.  The  pieces  of  skull  show 
that  the  forehead  was  very  short,  and  much  inclined." 
Professor  Spring  says,  "  The  form  of  these  crania  ap- 
proaches more  nearly  that  of  negroes,  and  not  at  all  to 
present  European  races.  The  occipital  bone  is  higher, 
the  lateral  sides  of  the  skull  much  more  flattened  and 
more  compressed  than  in  any  of  those  of  our  living 
races." 

There  can  be  no  doubt  that  Europe  was  once  inhabited 


LECTURES  ON  GEOLOGY.  269 

by  ravages  as  wild  and  barbarous  as  the  Digger  Indian 
or  the  Fuegian,  and  whose  intellectual  range  was  equally 
as  narrow,  or  even  more  so,  as  their  brain-cases  testify. 

In  1857,  a  human  skeleton  was  found  in  a  limestone 
cave  in  the  Neanderthal,  near  Diisseldorf,  Prussia.  The 
floor  was  covered  to  the  depth  of  four  or  five  feet  with 
a  deposit  of  mud,  mixed  with  rounded  fragments  of 
chert.  It  was  associated  with  some  remains  of  a  bear, 
and  is  now  believed  to  be  of  the  same  age  as  the  extinct 
animals  —  such  as  the  mammoth,  rhinoceros,  &c.  —  whose 
remains  have  been  so  frequently  discovered  in  drift- 
deposits.  Professor  Huxley  says  "  that  it  is,  beyond 
doubt,  traceable  to  a  period  at  which  the  diluvium  still 
existed.  The  thickness  of  the  bones  was  very  extraor- 
dinary, and  the  elevation  and  depression  for  the  attach- 
ment of  muscles  were  developed  in  an  unusual  degree. 
Some  of  the  ribs  also  were  of  a  singularly  rounded  shape 
and  abrupt  curvature,  which  was  supposed  to  indicate 
great  power  in  the  thora- 
cic muscles."  The  fore-  Fig.  54. 
head  is  narrow  and  low 
(Fig.  54).  When  exhibit- 
ed at  a  scientific  meeting 
at  Bonn,  doubts  of  its 
human  character  were  ex- 
pressed by  several  natu- 
ralists. Professor  Schaff-  Homo 
hausen  and  other  experi- 
enced geologists  declared  it  to  be  human,  but  were 
struck  with  the  resemblance  of  the  frontal  bone  to  that 
of  the  chimpanzee  and  gorilla.  It  is  certainly  the  most 
ape-like  human  skull  ever  observed  by  scientific  men. 
It  is,  in  places,  three-quarters  of  an  inch  thick ;  and  the 
bony  ridge  over  the  eyes  is  enormous. 


270  LECTURES  ON  GEOLOGY. 

Recent  discoveries  in  the  bone  caves  of  Gibraltar 
show  that  this  skull  is  not  alone.  The  greater  part  of 
a  cranium  was  found  in  bone  breccia,  in  Cochrane's 
Cave.  "  This  cranium,"  says  Mr.  Busk,  "  resembles  in 
all  essential  particulars,  including  its  great  thickness, 
the  far-famed  Neanderthal  skull.  Its  discovery  adds 
immensely  to  the  scientific  value  of  the  Neanderthal 
specimen,  if  only  as  showing  that  the  latter  does  not 
represent,  as  many  have  hitherto  supposed,  a  mere  in- 
dividual peculiarity,  but  that  it  may  have  been  charac- 
teristic of  a  race  extending  from  the  Rhine  to  the 
Pillars  of  Hercules." 

The  aboriginal  inhabitants  of  America  were  preceded 
by  others  lower  in  the  scale  than  themselves.  In  a  bone 
cave  in  Brazil,  Dr.  Lund  discovered  human  crania  mixed 
with  the  bones  of  extinct  animals,  in  which  the  forehead 
receded  on  a  level  with  the  face.  Castelnau  discovered, 
under  similar  conditions,  in  the  rocky  caverns  of  the 
Peruvian  Andes,  human  crania  of  a  similar  form. 

North  America  seems  to  have  been  peopled  also  by 
rude  races  at  a  very  early  period,  probably  preceding 
the  ancient  dwellers  on  the  banks  of  the  Somme,  whom 
Lyell  estimates  to  have  lived  one  hundred  thousand 
years  ago.  A  human  skull  was  found  by  Mr.  James 
Matson,  at  Altaville,  in  Calaveras  County,  California,  at 
a  depth  of  one  hundred  and  thirty  feet,  under  four  beds 
of  consolidated  volcanic  ash,  locally  known  as  lava,  as- 
sociated with  the  bones  of  an  extinct  rhinoceros,  camel, 
and  horse.  It  was  covered  and  partly  incrusted  with 
stony  matter.  The  base  of  the  skull  is  embedded  in  a 
mass  of  bone  breccia  and  small  pebbles  of  volcanic 
rock,  cemented  with  a  thin  layer  of  carbonate  of  lime. 
The  skull  resembles  those  of  the  present  Digger  Indians, 


LECTURES   ON   GEOLOGY.  271 

but  is  of  remarkable  thickness ;  a  feature  indicating  small 
use  of  the  brain  on  the  part  of  its  original  owner, 
mental  exercise  reducing* the  thickness  of  the  skull. 

It  must  not  be  supposed  that  we  have  yet  found  re- 
mains of  the  earliest  human  beings.  It  is  highly  proba- 
ble that  man  existed  during  the  pliocene  period,  when 
\ve  know  that  the  horse,  the  ox,  the  deer,  the  dog,  and 
other  familiar  animals,  abounded. 

The  immense  weight  of  the  ice  accumulated  during 
the  drift-period  seems  to  have  depressed  a  large  portion 
of  the  land  below  the  ocean-level,  owing,  probably,  to 
the  still  yielding  nature  of  the  earth's  crust ;  and  in  some 
places  the  ocean  continued  to  occupy  the  land  for  some 
time  after  the  icy  covering  melted.  Evidences  of  this 
are  common  along  the  coast  of  New  England,  around 
the  shores  of  Lake  Champlain,  and  in  various  parts  of 
Canada,  near  the  St.  Lawrence  and  its  tributaries,  and  in 
Nova  Scotia.  At  the  close  of  the  drift-period,  the  land 
slowly  rose  step  by  step,  leaving  terraces,  marking  the 
former  beaches  along  which  the  waves  rolled,  as  I  have 
seen  them  on  the  Lower  St.  Lawrence,  one  above  the 
other,  to  a  height  of  three  hundred  feet;  attesting  the 
successive  uplifts  to  which  the  land  has  been  subjected. 
Around  Lake  Champlain  there  has  been  an  elevation,  in 
some  places,  of  more  than  three  hundred  feet,  and  above 
four  hundred  near  Montreal ;  for  beds  are  found  at  tlicse 
elevations  abounding  in  marine  fossils. 

In  making  the  excavation  for  the  Rutland  and  Bui  ling- 
ton  Railroad,  a  fossil  whale,  about  fourteen  feet  long,  was 
found  in  blue  clay,  fourteen  feet  below  the  surface,  sixty 
feet  above  the  present  level  of  the  lake,  and  one  hundred 
and  iifty  feet  above  the  ocean.  Seals,  fishes,  and  immense 
nurn'  ers  of  shells,  have  been  discovered  in  beds  around 


272  LECTURES  ON  GEOLOGY. 

Lake  Champlain,  deposited  after  the  glacial  period,  and 
before  the  uprising  of  the  land  took  place ;  the  ocean 
passing  up  the  St.  Lawrence  (then  a  long  gulf),  and  con- 
necting  with  Lake  Champlain,  a  large  inland  sea. 

That  this  submergence  of  the  land  was  caused  by  the 
weight  of  the  ice  is  indicated  by  the  fact  that  the  great- 
est amount  of  submergence  took  place  in  the  arctic 
regions,  where  the  icy  covering  was  necessarily  the 
thickest,  for  there  the  old  sea-beaches  are  highest :  they 
are  higher  on  the  St.  Lawrence  than  in  Southern  New 
England  ;  and  the  northern  terraces  on  the  Great  Lakes 
are  higher  than  those  farther  south. 

ALLUVIAL  PERIOD. 

More  recent,  generally,  than  the  drift-beds,  are  the 
alluvial  deposits,  some  of  which  are  in  process  of  forma- 
tion to-day.  The  world  is  by  no  means  finished  yet. 
Ever  the  water  flows,  the  wind  blows,  the  grass  grows, 
the  earthquakes  heave,  the  waves  dash  ;  ever  the  de- 
stroyers pull  down  the  old  world,  ever  the  builders  erect 
the  new.  Among  the  sayings  attributed  to  Pythagoras  by 
Ovid,  we  have  the  following :  "  Nothing  perishes  in  this 
world ;  but  things  merely  vary,  and  change  their  form.'' 
As  evidences  of  this,  he  says,  "  Solid  land  has  been  con- 
verted into  sea.  Sea  has  been  changed  into  land.  Marine 
shells  lie  far  distant  from  the  deep,  and  the  anchor  has 
been  found  on  the  summit  of  hills.  Valleys  have  been 
excavated  by  running  water,  and  floods  have  washed 
down  hills  into  the  sea.  Marshes  have  become  dry 
ground.  Dry  lands  have  been  changed  into  stagnant 
pools.  Volcanic  vents  shift  their  position  :  there  was  a 
time  when  ^Etna  was  not  a  burning  mountain,  and  the 


LECTURES  ON  GEOLOGY.  273 

time  will  come  when  it  will  cease  to  burn."  Aris- 
totle says,  "  The  distribution  of  land  and  sea  in  par- 
ticular regions  does  not  endure  throughout  all  time ; 
but  it  becomes  sea  in  those  parts  where  it  was  land,  and 
again  it  becomes  land  where  it  was  sea.  The  same  tracts, 
therefore,  are  not,  some  always  sea,  and  others  always 
continents;  but  every  thing  changes  in  course  of  time." 
Mohammed  Kazwina,  an  Arabian  writer  of  the  seventh 
century,  embodied  the  idea  in  a  fine  conception,  which 
has  been  thus  translated  and  versified:  — 

"  I  wandered  by  a  goodly  town 
Beset  with  many  a  garden  fair, 
And  asked,  of  one  who  gathered  down 
Large  fruit,  how  long  the  town  was  there. 
He  spoke,  nor  chose  his  hand  to  stay : 
1  The  town  has  stood  for  many  a  day, 
And  will  be  here  forever  and  aye.' 

A  thousand  years  went  by,  and  then 

I  visited  the  place  again  : 

No  vestige  of  that  town  I  traced. 

But  one  poor  swain  his  horn  employed : 

His  sheep,  unconscious,  browsed  and  grazed. 

I  asked,  When  was  the  town  destroyed  ? 

He  spoke,  nor  would  his  horn  lay  by : 

'  One  thing  may  grow,  and  another  die : 

But  I  know  nothing  of  towns ;  not  I/ 

A  thousand  years  went  by,  and  then 
I  wandered  past  the  spot  again. 
There,  in  the  deep  of  waters,  cast 
His  nets  a  lonely  fisherman ; 
And,  as  he  drew  them  up  at  last, 
J  asked  him  how  the  lake  began. 
He  looked  at  me,  and  laughed  to  say, 
*  The  waters  spring  forever  and  aye, 
And  fish  are  plenty  every  day.' 
18 


274  LECTURES  ON  GEOLOGY. 

A  thousand  years  went  by,  and  then 
I  saw  the  selfsame  place  again. 
And,  lo !  a  country  wild  and  rude ; 
And,  axe  in  hand,  beside  a  tree, 
The  hermit  of  that  solitude, 
I  asked  how  old  the  wood  might  be. 
He  said,  *  I  count  not  time  at  all ; 
A  tree  may  rise,  a  tree  may  fall ; 
The  forest  overlives  us  all.' 

A  thousand  years  went  by,  and  then 

I  went  the  same  old  round  again  ; 

And  there  a  glorious  city  stood ; 

And,  'mid  tumultuous  market-cry, 

I  asked,  When  rose  the  town  where  wood, 

Pasture,  and  lake  forgotten,  lie  ? 

They  heard  me  not ;  and  little  blame. 

For  them  the  world  is  as  it  came ; 

And  all  things  must  be  still  the  same. 

A  thousand  years  shall  pass,  and  then 
I  mean  to  try  that  road  again." 

And,  if  he  does,  the  sea  may  be  there,  and  gallant 
ships  go  sf-.iling  by.  So  goes  the  world,  though  multi- 
tudes have  no  conception  of  it.  At  the  close  of  one 
of  my  lectures,  a  gentleman  came  up,  and  remarked  to 
ine  that  he  believed  the  world  was  made  "just  exactly 
as  it  is."  —  "What!"  said  I,  "down  to  the  cart-ruts ?r 
—  "No-o:  not  exactly  down  to  the  cart-ruts."  —  "Then 
not  to  the  river-ruts ;  for,  as  the  carts  have  ruts  to  run  in 
that  their  wheels  have  made,  so  the  rivers  have  ruts  to 
run  in  that  their  wheels  have  made."  See  what  Niagara 
has  done  !  Six  hundred  and  seventy  thousand  tons  of 
water  falling  every  minute  over  a  limestone  ledge  is 
wearing  it  back  at  the  rate,  says  Lyell,  of  a  foot  a  year. 
Observers  on  the  spot,  whom  I  have  conversed  with,  say 


LECTURES  ON  GEOLOGY.  275 

less.  But  suppose  it  a  foot  a  year:  it  has  then  taken 
thirty-five  thousand  years  to  cut  its  way  back  from 
Queenstown,  seven  miles  below,  where  it  once  was,  to 
Niagara,  where  it  is  now. 

Below  Rochester,  the  Genesee  has  cut  its  way  back 
for  seven  miles  through  rocks  of  three  different  degrees 
of  hardness,  that  have  worn  away  with  unequal  rapidity; 
so  that  there  are  three  cataracts,  miles  apart.  These 
are  trifling  operations  compared  with  what  water  has 
accomplished  in  other  places.  In  New  Mexico,  Texas, 
Colorado,  and  California,  there  are  long,  deep  gulfs, 
called  "  canyons,"  where,  for  days  together,  the  traveller 
can  find  no  place  to  cross;  and,  though  water  is  in  sight, 
there  is  no  chance  to  obtain  it.  Grand  Canyon,  on  Cana- 
dian River,  is  two  hundred  and  fifty  feet  deep,  and 
fifty  miles  long.  Capt.  Marcy  describes  a  canyon  in 
Texas,  on  Red  River,  seventy  miles  long,  and  from  five 
hundred  to  eight  hundred  feet  deep.  In  some  places  on 
the  Colorado,  they  are  more  than  a  mile  deep,  —  a  thou- 
sand feet  in  solid  granite. 

But  what  is  this  compared  with  the  disintegrating 
action  of  the  ocean,  incessantly  battering  its  banks, 
and  making  continual  inroads  on  the  land?  At  Cape 
May,  it  was  proved  by  measurement,  that,  from  1804  to 
1820,  the  sea  encroached  on  the  land  at  the  rate  of  nine 
feet  a  year.  At  Sullivan's  Island,  near  Charleston,  in 
South  Carolina,  the  sea  carried  away  a  quarter  of  a  mile 
in  three  years.  Near  Boston  Harbor,  the  islands  are 
rapidly  wasting  away  under  the  influence  of  the  Atlantic 
waves ;  and  on  one  of  them,  Deer  Island,  an  extensive 
wall  of  stone  has  been  erected  to  arrest  the  work  of 
destruction.  It  has  been  calculated  that  one  thousand 
tons  of  earthy  matter  are  transported  daily  from  fa* 
coast  of  Long  Island,  seaward. 


27G  LECTURES  ON  GEOLOGY. 

The  des.ructive  agency  of  the  sea  can  be  most  readily 
seen  in  Nova  Scotia,  on  the  Bay  of  Fundy.  From  Briar 
Inland,  in  the  south,  to  Cape  Blomidon,  in  the  north,  the 
amygdaloidal  traps,  which  form  in  many  places  cliffs 
several  hundred  feet  high,  are  rapidly  wasting  away. 
Every  spring,  immense  masses  of  rock  are  dislodged 
from  them,  and  the  debris  reduced  by  the  waves  to  mud, 
and  swept  seaward.  The  trap  displayed  at  Cape  D'Or 
and  Partridge  Island,  on  the  western  side  of  the  Bay  of 
Fundy,  was  once  continuous  with  that  on  the  eastern 
side.  Cut  through  by  a  river,  probably,  at  first,  it  has 
since  been  wasted  away  by  the  action  of  the  waters  of 
the  Bay,  till  at  Cape  D'Or  there  is  a  width  of  seven 
miles :  and  a  few  centuries  will  destroy  all  vestiges 
of  volcanic  agency  on  the  western  side  of  the  Bay  of 
Fundy. 

Crossing  the  ocean  to  the  Island  of  Great  Britain, 
"  where  they  measure  land  by  the  inch/'  we  can  obtain 
a  better  idea  of  what  the  ocean  is  doing,  because 
greater  attention'is  paid  to  its  ravages.  Land  is  dearer, 
population  more  dense ;  and  intelligent  persons  have 
been  watching  the  process,  and  recording  it,  for  hun- 
dreds of  years.  North  of  Scotland,  the  Orkney  and 
Shetland  Islands,  though  made  of  the  hardest  and  most 
enduring  materials,  have  been  worn  away  to  mere 
needles.  On  the  coast  of  Durham,  between  Sunderland 
and  Hartlepool,  where  magnesian  limestone  cliffs  of  the 
Permian  formation  front  the  German  Ocean,  there  are 
caves  innumerable,  made  by  the  rolling  waves.  In  a 
stormy  time,  the  waves  lift  up  masses  of  rock,  that  weigh 
hundreds,  or  even  thousands,  of  pounds,  and  play  with 
them  as  a  boy  does  with  a  ball.  Against  the  face  of  the 
cliff  they  are  driven  with  terrible  force:  if  one  placa 


LECTURES  ON  GEOLOGY.  277 

is  softer  than  another,  it  is  soon  discovered,  and  a  cave 
is  in  time  hollowed ;  where  two  exist  contiguous,  the 
space  is  eaten  away  between  them,  the  unsupported 
roof  falls,  and  the  sea  has  made  a  permanent  inroad  into 
the  land. 

Proceeding  southward  along  the  eastern  coast  of 
England,  we  come  to  Yorkshire,  the  cliffs  of  which  are 
crumbling  away  along  its  whole  extent.  At  Whitby 
there  is  an  old  abbey,  or  was  when  I  was  there,  perched 
on  the  edge  of  the  cliff.  Ask  why  they  built  it  so  close 
to  the  cliff,  and  they  will  tell  you,  that,  when  it  was  built, 
it  was  a  mile  and  a  half  inland,  and  the  sea  has  swal- 
lowed the  land  that  lay  between  them.  Auburn,  Hart- 
burn,  and  Hyde  are  towns  known  only  in  history  and 
tradition :  their  bones  lie  beneath  the  German  Ocean ; 
and  fishes  swim  where  men  have  been.  At  Owthorne, 
the  annual  encroachment  for  many  years  was  about 
twelve  feet.  The  cliffs  of  Norfolk  and  Suffolk  are  wear- 
ing away  with  great  rapidity.  The  ancient  villages  of 
Shipden,  Wimpwell,  and  Eccles,have  disappeared.  The 
whole  site  of  the  ancient  town  of  Cromer  has  been 
swept  away,  and  ships  sail  over  where  the  houses  were. 
South  of  this,  the  cliffs,  it  is  estimated,  are  going  at  the 
rate  of  three  feet  annually. 

Dunwich,  in  Suffolk,  was  once  a  place  of  much  impor- 
tance, containing  at  one  time  fifty-two  churches  and 
monasteries.  A  monastery  went  at  one  time,  at  another 
several  churches,  and  subsequently  four  hundred  houses 
at  once.  "  Ancient  writings  make  mention  of  a  wood  a 
mile  and  a  half  to  the  east  of  Dunwich,  the  site  of  which 
at  present  must  be  so  far  within  the  sea.7'  The  sea  is 
now  twenty-four  feet  deep  where  the  town  of  Aid7  trough 
once  stood. 


278  LECTURES  ON  GEOLOGY. 

Farther  south,  we  come  to  the  mouth  of  the  Thames 
and  the  Isle  of  Sheppey,  which  is  composed  of  London 
clay,  and  decays  very  rapidly.  In  1780,  the  Church  of 
Minster,  now  near  the  coast,  is  said  to  have  been  in  the 
middle  of  the  island.  In  a  few  years,  some  say  thirty, 
the  island,  which  is  about  six  miles  long  by  four  broad, 
will  be  taken  into  the  never-to-be-satisfied  maw  of  the 
sea.  In  the  county  of  Kent,  we  find  Reculver,  with 
its  ancient  church,  on  the  very  edge  of  the  cliff:  in 
the  time  of  Henry  VIII.,  it  was  a  mile  distant.  In  1834, 
wooden  piles  were  driven,  and  a  stone  breakwater  built, 
to  save  the  church.  The  sea  never  relaxes  its  vigilance 
for  a  moment,  and  will  some  day  seize  its  prey.  li- 
nearly every  instance  where  cliffs  abut  on  the  sea,  they 
are  being  worn  away  by  the  action  of  the  waves,  how- 
ever hard  the  material  may  be  of  which  they  are  com- 
posed. There  is  little  doubt  that  England  arid  France 
were  once  united,  probably  within  the  human  period; 
and  the  division  that  an  earthquake  may  have  com- 
menced, the  sea  has  enlarged,  and  is  constantly  increasing. 

Some  parts  of  Holland  have  been  terribly  devastated 
by  the  sea.  North  Friesland  was,  in  the  year  1240,  a 
flourishing  district  ten  miles  long,  and  seven  miles  broad. 
Toward  the  end  of  the  sixteenth  century,  it  was  only  four 
miles  round.  In  the  year  1634,  a  flood  passed  over  the 
whole  island,  when  thirteen  hundred  houses  with  many 
churches  were  lost  :  fifty  thousand  head  of  cattle 
perished,  and  above  six  thousand  men.  Three  small 
islets  remained ;  but  they  are  wasting  away. 

Is  this,  then,  to  be  the  fate  of  the  world  ?  Must  the 
hungry  sea  swallow  all,  and  the  waves  chant  forever  the 
funeral  dirge  of  the  lost,  lost  land  ?  There  is  no  danger. 
The  universe  abounds  with  checks  and  counterbalances: 


LECTURES  ON  GEOLOGY.  279 

the  existence  of  the  earth  as  it  is,  and  man  upon  it,  is 
evidence  of  this.  More  rapidly  than  the  sea  eats  away 
the  land,  bhe  land  gains  upon  the  sea.  There  is  a  greater 
land-surface  on  the  face  of  the  world  to-day  than  at  any 
past  period  in  its  history,  and  this  is  constantly  in- 
creasing. How  is  this  done  \  Away  up  in  the  moun- 
tains, the  rain  and  the  frost  loosen  a  massive  rock  from  its 
seat  of  ages,  and  down  it  falls  into  the  bed  of  a  torrent. 
In  time,  it  is  broken  into  pieces  as  large  as  a  flour-barrel ; 
and  these  are  swept  down,  rolling  one  against  the  other, 
till  they  are  no  larger  than  a  man's  fist.  Now  they 
are  swept  along  with  the  greatest  ease;  for  a  stream 
flowing  at  the  rate  of  four  miles  an  hour  can  do  that :  on 
they  go,  till  they  are  ground  to  sand,  and  then  to  im- 
palpable powder ;  never  resting  till  they  are  swept  into 
the  ocean,  and  settle  down  to  make  new  rock,  some  day 
to  become  dry  land,  and  be  inhabited. 

"  Lofty  mountains,  whose  tops  appear  to  shroud 
Their  granite  peaks  deep  in  the  vapory  cloud, 
Worn  by  the  tempest,  wasted  by  the  rains, 
Sink  slowly  down  to  fill  wide  Ocean's  plains." 

Every  shower  washes  material  down  from  the  hills 
into  the  plains,  and  thence  eventually  to  the  ocean ;  and, 
where  the  earth  is  loose,  the  streams  become  so  charged 
with  it,  as  I  have  seen  them  in  Western  Colorado,  as  to 
flow  with  mud  instead  of  water. 

The  Mississippi  displays  on  the  grandest  scale  the 
action  of  running  water.  Three  thousand  miles  from 
its  source,  "  where  the  fur-hunter  roams  the  wilderness 
for  his  peltries,'7  it  pours  its  turbid  waters  into  the  Gulf 
of  Mexico  in  the  region  of  the  cotton,  rice,  and  sugar. 
Its  alluvial  plain  is  from  fifty  to  ninety  miles  wide,  made 


280  LECTURES  ON  GEOLOGY. 

by  the  liver  swinging  from  side  to  side  like  a  mighty 
pendulum,  marking  the  seconds  of  the  grand  geologic 
periods.  The  land  formed  by  the  sediment  carried  down 
in  its  waters  contains  thirteen  thousand  six  hundred 
square  miles.  It  is  said  to  gain  on  the  Gulf  at  the  rate 
of  one  mile  in  a  century.  The  outer  crest  of  the  bar  of 
the  South-west  Pass  advances  into  the  Gulf  three  hun- 
dred and  thirty-eight  feet  annually.  The  coarser  sedi- 
ment is  deposited  near  the  mouth  :  but  the  finer  is  swept 
on  by  the  current  of  the  stream,  slowly  sinking  as  it  goes  ; 
and  is  distributed  widely  over  the  sea-bottom,  there  to  be 
consolidated  in  time  into  rock,  when  the  pressure  of  the 
sediment  above  it  becomes  sufficiently  great,  and  time 
has  been  given  to  harden  it.  It  has  been  estimated  that 
four  billion  cubic  feet  01  mud  are  carried  down  every 
year,  or  sufficient  to  cover  a  township,  containing  thirty- 
six  square  miles,  to  the  depth  of  forty  feet.  It  would 
take  forty  thousand  locomotives,  taking  a  thousand  tons 
a  trip,  and  making  a  trip  a  week,  to  transport  as  much 
solid  material  as  this  mighty  river  sweeps  down  sus- 
pended in  its  waters. 

The  Amazon  of  South  America  probably  carries  down 
a  larger  amount  of  sediment  than  the  Mississippi ;  but 
the  Gulf  Stream,  sweeping  past  its  mouth  at  the  rate  of 
four  miles  an  hour,  prevents  the  formation  of  a  delta,  and 
carries  its  sediment  out  into  the  ocean.  Its  turbid 
waters  can  be  distinguished  three  hundred  miles  from 
its  mouth ;  and  the  fine  sediment  must  be  transported 
much  farther  than  this. 

It  is  generally  where  rivers  empty  into  a  lake,  sea,  or 
ocean,  that  deposits  of  land  are  now  being  made.  In 
most  cases,  they  are  called  "  deltas,"  from  the  Greek 
name  for  the  letter  c?,  to  the  shape  of  which  (A)  they 
beaj  some  resemblance. 


LECTURES  ON  GEOLOGY.  281 

That  Egypt  was  the  gift  of  the  Nile  was  a  common 
expression  in  thai  country  more  than  two  thousand 
years  ago.  It  is  supposed  that  the  sea  once  washed 
the  base  of  the  rocks  on  which  the  Pyramids  of  Mem- 
phis stand ;  and  all  the  land  lying  between  has  been 
deposited  by  the  river.  It  has  swept  down  from  the 
mountains  of  Abyssinia  the  fine  mud  that  lines  its 
fertile  valley,  and  has  formed  a  delta  at  its  mouth  as 
large  as  the  State  of  Vermont. 

The  Lake  of  Geneva  is  about  forty  miles  long,  and 
from  two  to  eight  broad.  The  waters  of  the  River 
Rhone  enter  it  at  the  eastern  end,  turbid,  and  highly 
discolored,  but  leave  it  at  the  western  end,  near  Geneva, 
beautifully  clear  and  transparent.  Thus  the  lake  is 
filling  up  with  the  sediment  deposited  from  the  waters 
of  the  river :  so  that  an  ancient  town  called  Port  Vallais, 
once  situated  at  the  water's  edge,  near  the  eastern  end, 
is  now  a  mile  and  a  half  inland ;  that  amount  of  land 
having  been  made  in  about  eight  centuries.  In  time, 
the  whole  of  the  lake  will  be  filled,  and  a  rich  agricul- 
tural district  take  its  place.  Millions  of  acres  that 
farmers  now  plough  have  been  formed  in  a  similar 
manner. 

The  Ganges  and  Brahmapootra,  the  two  principal 
rivers  of  India,  descending  from  the  highest  mountains 
in  the  world,  and  passing  through  a  country  where  the 
rain-fall  is  very  great,  take  down  an  immense  amount  of 
solid  material.  There  is  nothing  as  fine  as  gravel  within 
four  hundred  miles  of  the  mouth  of  the  Ganges ;  it  is  all 
fine  mud  brought  down  by  the  stream :  while  the  united 
delta  of  these  streams  is  as  large  as  the  State  of  New 
York.  It  has  been  computed  that  the  Ganges  alone  carries 
into  the  Bay  of  Bsngal,  every  year,  seven  thousand  million 


282  LECTURES  ON  GEOLOGY. 

( 

tons  }f  mud,  or,  in  other  words,  a  mass  of  material  more 
than  sixty  times  as  large  and  heavy  as  the  Great  Pyra- 
mid of  Egypt,  whose  base  covers  eleven  acres,  and 
whoue  height  is  four  hundred  and  fifty  feet. 

The  Po  and  the  Adige,  two  European  streams  flowing 
into  the  Adriatic  Sea,  or  Gulf  of  Venice,  have  caused 
a  hundred  miles  of  coast  to  encroach  on  the  gulf  from 
two  to  twenty  miles  in  two  thousand  years.  The  city 
of  Adria,  which  was  a  seaport  in  the  time  of  Augustus, 
and  gave  its  name  to  the  gulf,  is  now  twenty  miles  in- 
land. Thus  the  Gulf  of  Mexico,  the  Bay  of  Bengal,  and 
the  Gulf  of  Venice,  are  steadily  filling;  being  slowly 
converted  into  dry  land,  which  will  represent  this  period, 
as  the  old  formations  represent  the  periods  of  the  past. 
During  the  war,  down  sank  into  the  bed  of  the  Missis- 
sippi the  boats  of  contending  parties ;  side  by  side  lie 
the  bodies  of  Federal  and  Rebel ;  coins,  jewels,  clocks, 
watches,  pottery,  cutlery,  books  on  all  subjects,  and  a 
thousand  machines  and  implements.  The  fine  mud 
settles  around  them  as  they  sink ;  and  in  time  many  will 
become  fossils  in  the  solid  rock.  When  our  libraries 
shall  have  perished,  our  newspapers  be  forgotten,  and 
our  most  cherished  names  be  lost  in  the  millions  suc- 
ceeding them,  even  then  Nature  shall  preserve  her 
faithful  diary ;  for  there  is  nothing  too  trivial  for  her 
notice,  too  slight  for  her  regard.  At  some  time,  the 
bottom  of  the  Gulf  of  Mexico  will  be  elevated  above 
the  sea-level ;  rivers  will  course  over  it,  exposing  the 
rocks  making  to-day  on  the  right  hand  and  on  the  left ; 
men  will  open  quarries  in  them  to  build  cities,  and  the 
•works  and  remains  of  this  age  will  come  to  light.  I 
can  imagine  with  what  feelings  of  astonishment  the 
scientific  men  of  that  age  will  view  a  fossil  hoop-skirt 


LECTURES  ON  GEOLOGY.  283 

or  a  capacious  Dutch  tobacco-pipe,  and  what  singular 
notions  they  will  entertain  of  the  semi-barbarians  who 
live  in  these  days. 

In  the  play  of  "  Richard  III.,"  George,  Duke  of  Clar- 
ence, relates  to  Brakenbury,  in  the  Tower,  a  fearful 
dream :  — 

"  Metliought  I  saw  a  thousand  fearful  wrecks ; 
A  thousand  men  that  fishes  gnawed  upon ; 
Wedges  of  gold,  great  anchors,  heaps  of  pearl, 
Inestimable  stones,  unvalued  jewels,  — 
All  scattered  in  the  bottom  of  the  sea. 
Some  lay  in  dead  men's  skulls ;  and,  in  those  holes 
Where  eyes  did  once  inhabit,  there  were  crept 
(As  'twere  in  scorn  of  eyes)  reflecting  gems, 
That  wooed  the  slimy  bottom  of  the  deep, 
And  mocked  the  dead  bones  that  lay  scattered  by." 

In  the  Museum  of  the  Boston  Natural-history  Society 
are  fossil  wine-decanters  and  a  ship-bell.  I  have  seen 
English  guineas  in  conglomerate,  taken  from  the  wreck 
of  the  British  man-of-war  "  Huzzar ;  "  the  solid  conglom- 
erate, formed  by  oxide  of  iron,  binding  together  the 
flint  pebbles  of  which  the  ballast  was  composed.  I 
have  seen  silver  pennies  of  Edward  L,  in  breccia,  found 
at  the  depth  of  ten  feet  in  the  bed  of  the  River  Dove, 
in  Derbyshire,  in  1832.  They  came  from  a  military 
chest  lost  in  this  stream  in  1322  :  the  soldiers,  being 
alarmed  by^a  sudden  panic,  threw  the  chest  into  the 
river.  Many  thousand  silver  coins,  English,  Irish,  and 
Scotch,  were  found  in  a  hard  conglomerate.  The  full 
significance  of  the  fossils  formed,  and  thus  forming,  we 
are  far  from  comprehending  yet :  they  will  convey  to 
the  fut  ire  student  much  more  than  the  geologist  at 
present  Ireams  of. 


284  LECTURES  ON  GEOLOGY. 

There  is  no  danger,  then,  that  the  sea  will  swallow  up 
the  land:  the  land,  in  fact,  gains  on  the  one  hand  more 
than  the  sea  sweeps  off  on  the  other.  Bat  will  not  the 
degrading  influences,  whose  existence  and  operation 
have  been  demonstrated,  reduce  the  earth  to  a  dull, 
monotonous  plain  ?  The  rain,  falling  on  the  mountains, 
is  constantly  sweeping  fine  particles  into  the  valley,  and 
there  are  no  streams  to  return  them :  frost  and  ice  are 
equally  employed  in  wearing  down  the  high  places. 
Millions  of  laborers,  day  and  night,  employed  in  levelling 
the  earth,  what  can  withstand  their  power?  They  have 
been  at  work  for  millions  of  years,  and  yet  the  hills  and 
mountains  survive ;  or,  if  thousands  have  been  levelled, 
thousands  more  have  taken  their  place.  A  cooling 
globe,  such  as  the  earth  is  known  to  be,  is  necessarily 
a  shrinking  globe.  A  shrivelled  apple  is  such  in  conse- 
quence of  the  inside  becoming  too  small  for  the  skin  on 
the  outside,  which  shrivels  to  accommodate  itself  to  the 
changed  conditions.  The  crust  of  the  earth  was  first 
formed  when  the  earth  was  much  larger:  it  fitted  the 
earth  at  first,  as  the  skin  does  a  green  apple  ;  but,  as  the 
earth  diminished  in  consequence  of  parting  with  its 
heat,  its  rocky  covering  has  been  ridged  into  hills  and 
mountains,  and  shrunk  into  valleys.  Thus  the  crust  of 
the  earth  is  constantly  rising  or  falling,  accommodating 
itself  to  the  shrinking  interior,  the  heat  of  which  is 
passing  off  by  volcanoes,  hot-springs,  and  by  conduction 
through  the  rocks  to  the  surface.  Thus  it  is  known  that 
the  western  coast  of  Greenland,  fora  space  of  more  than 
six  hundred  miles,  is  slowly  sinking.  "  Ancient  buildings 
en  low,  rocky  islands,  and  on  the  shore  of  the  mainland, 
1  ave  been  gradually  submerged ;  and  experience  has 
taught  the  aboriginal  Greenlander  never  to  build  his 


LECTURES  ON  GEOLOGY.  285 

but  near  ,he  water's  edge.  In  one  place,  the  Moravian 
settlers  have  been  obliged  more  than  once  to  move  in- 
land the  poles  upon  which  their  large  boats  were  set ; 
md  the  old  poles  still  remain  beneath  the  water  as  silent 
witnesses  of  the  change." 

For  many  years,  a  discussion  was  carried  on  regard- 
ing the  alteration  of  level  on  the  peninsula  of  Sweden 
ind  Norway.  To  decide  the  matter,  lines,  or  grooves, 
were  cut  in  the  rocks  at  the  water's  level  on  the  shore 
of  the  Baltic.  If  the  land  should  rise  or  sink,  since 
there  are  no  observable  tides  on  the  Baltic,  those  marks 
would  tell  the  story.  Fourteen  years  afterward,  they 
were  examined  by  Lyell,  who  found  there  had  been  a 
rise  of  four  or  five  inches.  This  rise  seems  to  have  been 
going  on  for  a  long  period,  as  masses  of  shells  have  been 
found  on  old  sea-beaches  two  hundred  feet  above  the 
present 'level  of  the  sea,  containing  only  such  species  as 
now  live  there.  South  of  Stockholm,  the  peninsula  is 
saidto  be  slowly  sinking. 

At  Spitzbergen,  drift-wood,  and  bones  of  whales,  have 
been  found  several  miles  inland,  and  at  least  thirty  feet 
above  high-water  mark. 

"  The  coast  of  Denmark  on  the  Sound,  the  Island  of 
Saltholrn,  opposite  to  Copenhagen,  and  that  of  Bornholm, 
are  rising,  —  the  latter  at  the  rate  of  a  foot  a  century. 
The  coast  of  Memel,  on  the  Baltic,  has  actually  risen  a 
foot  and  four  inches  within  the  last  thirty  years." 

In  England  and  Scotland,  the  land  has  in  many  places 
been  rising  for  ages,  as  the  presence  of  elevated  sea- 
beaches  along  the  coast  testifies. 

No  better  evidence  can  be  found  of  the  elevations  and 
subsidences  to  which  the  earth's  crust  is  subject  than 
that  of  the  Temple  of  Jupiter  Serapis  at  Puzzuoli. 


23(5  LECTURES   ON   GEOLOGY. 

Origin  illy,  the  temple  had  twenty-four  granite  columns, 
and  twent}M;wo  of  marble,  each  hewn  from  a  single 
stone.  Three  of  these  columns  remain  erect,  the  tallest 
forty-two  feet  high.  They  are  smooth  and  uninjured  to 
the  height  of  twelve  feet ;  but  above  that  are  bands  of 
holes  nine  feet  wide,  made  by  the  boring  of  sea-mussels, 
some  of  the  shells  still  occupying  them.  Above  these 
bands,  the  columns  are  smooth  to  their  summits.  It  is 
evident  that  the  pillars  were  once  below  the  level  of  the 
sea,  their  lower  portions  being  protected  by  rubbish ;  and 
since  that  time  they  have  been  elevated  twenty-three 
feet,  without  disturbing  the  columns,  which,  as  Moore 
says,  — 

"  Stand  sublime, 

Flinging  their  shadows  from  on  high, 
Like  dials  which  the  wizard  Time 
Had  raised  to  count  his  ages  by." 

There  is  reason  to  believe  that  Newfoundland  is  rising 
out  of  the  sea.  In  the  neighborhood  of  Conception  Bay, 
large,  flat  rocks  exist,  over  which  schooners  used  to  pass 
thirty  or  forty  years  ago :  now  the  water  over  them  is 
scarcely  navigable  for  a  skiff. 

The  southern  coast  of  Nova  Scotia  is  rising.  Near 
Salmon  River  are  bluffs  fifty  feet  high,  containing  shells, 
most  of  which  are  identical  with  those  in  the  contiguous 
sea. 

At  Tadousac,  on  the  St.  Lawrence,  below  Quebec,  are 
old  sea-beaches  from  fifty  to  three  hundred  feet  above 
the  present  level  of  the  water.  They  have  been  favorite 
places  of  resort  for  old  Indian  tribes:  their  stone 
weapons  ie  scattered  over  them  in  the  greatest  abun- 
dance. 


LECTURES  ON  GEOLOGY.  287 

Near  Lima,  in  South  America,  Darwin  found  proofs 
that  the  ancient  bed  of  the  sea  had  been  raised  more 
than  eighty  feet  within  the  human  period  ;  strata  having 
been  found  at  that  height  above  the  sea-level,  containing 
pieces  of  cotton  thread  and  plaited  rush  with  seaweed 
and  marine  shells. 

Sometimes  elevations  and  subsidences  are  made  by 
earthquake  agency  ;  and  at  such  times  the  land  rises  or 
sinks  with  great  rapidity.  In  1819,  an  earthquake 
occurred  at  Cutch,  in  the  delta  of  the  Indus.  The  fort 
and  village  of  Sindree  were  submerged,  the  tops  only  of 
the  houses  appearing  above  the  water.  Two  thousand 
square  miles  of  land  were  converted  into  a  lake  ;  but, 
immediately  after  the  shock,  a  mound  fifty  miles  long, 
fifteen  miles  wide,  and  ten  feet  high,  arose  within  a  few 
miles  of  the  place  of  subsidence. 

In  1822,  the  coast  of  Chili,  after  an  earthquake,  was 
permanently  elevated  from  two  to  six  feet,  through  an 
area  calculated  to  be  one  hundred  thousand  square  miles 
in  extent. 

We  shall  have,  then,  for  the  ages  to  come,  the  giant 
mountains  with  their  snowy  crests,  lifting  up  the  souls 
of  millions  yet  to  be  born,  and  giving  them  visions  of 
beauty  and  grandeur.  We  shall  have  our  verdant  hills, 
from  which  shall  go  laughing  rills  on  their  beneficent  mis- 
sion  ;  and  flowery  vales,  where  the  lovers  of  the  coming 
time  shall  walk  and  rejoice  in  the  varied  prospect  spread 
before  them. 

The  continual  changes  taking  place  in  the  inorganic 
world  are  accompanied  by,  and  to  some  extent  pioduc- 
tive  of,  continued  change  in  the  organic  world.  The 
mastodon,  the  mammoth,  the  cave  bear,  the  Irish  elk, 
the  woolly-haired  rhinoceros,  and  many  other  animals, 


288  LECTURES  ON  GEOLOGY. 

have  become  extinct  within  the  human  period ;  some  of 
them,  such  as  the  dodo  and  solitaire,  within  a  few  cen< 
turies.  Many  vegetable  forms  have  doubtless  perished 
in  like  manner  ;  though,  being  less  conspicuous,  and  more 
difficult  of  preservation  as  fossils,  we  are  not  as  well 
acquainted  with  those  that  have  become  extinct. 

Accompanying  this  extinction  of  the  old  is  the  crea- 
tion of  the  new.  New  varieties,  which  it  is  now  generally 
acknowledged  are  incipient  species,  come  into  being 
every  year.  Many  perish ;  some  live,  struggle,  perpetu- 
ate, and  eventually  give  us  new  species  of  animals  and 
plants  better  adapted  to  present  conditions  than  the  old. 
Thus  is  the  face  of  the  earth  renewed  from  age  to  age, 
and  its  continual  progress  guaranteed. 


LECTURE   VI. 


THE  FUTURE  OF  THIS  PLANET  AND  ITS  INHABITANTS. 

WIDE  as  humanity,  and  inseparable  from  our  very 
nature,  is  the  disposition  to  look  into  the  future.  As 
the  traveller  on  the  highway  eagerly  views  the  road 
that  lies  before  him,  so  the  travellers  on  life's  pathway 
climb  the  hills,  and  peer  through  the  clouds  and  fogs, 
to  catch  a  glimpse  of  the  path  that  they  are  destined  to 
walk.  To  gratify  this  disposition,  the  astrologer  con- 
sults the  stars  in  nightly  watches,  and  interrogates  them 
regarding  the  influence  he  supposes  them  to  have  on 
human  destinies ;  the  cheiromancer  scrutinizes  the  lines 
of  the  hand  to  find  some  connection  between  them  and 
the  lines  of  individual  fate ;  the  necromancer  seeks  to 
call  up  the  very  dead,  and  wrest  from  their  skeleton 
fingers  the  key  that  shall  unlock  the  secrets  of  the 
future. 

Nor  is  this  disposition  confined  to  the  vulgar.  It  is 
shared  in  alike  by  the  peasant  and  the  prince,  the  poet, 
the  prophet,  and  the  philosopher;  nor  without  avail. 
In  every  age  there  have  been  men  and  women,  who, 
soaring  into  the  sky  like  larks,  have  seen  the  rays  of  the 
rising  day  before  its  beams  have  reached  the  earth,  and 
sung  of  its  glories  in  the  ears  of  the  drowsy  world 
lying  in  the  twilight  below. 

10  «89 


290  LECTURES  ON  GEOLOGT. 

The  World  holds  her  hand  to  us  ;  and  we  read  the  lines 
that  the  ages  have  carved  thereon,  and  from  them  un- 
hesitatingly state  what  will  be  her  coming  history.  She 
gives  us,  in  geology,  all  the  necessary  elements  ;  and 
we  calculate  her  nativity. 

Can  any  one  really  tell  what  will  be  ?  Can  any  un- 
assisted mortal  reveal  what  the  future  has  in  store  for 
our  planet?  Assuredly  he  can,  with  such  assistance 
only  as  Nature  gives  to  her  faithful  students.  As 
certainly  as  we  can  tell,  when  looking  on  the  gigantic 
forest-tree,  the  pride  of  the  woods,  that  the  time  will 
come  when  it  shall  lie  prostrate  on  the  ground,  and  give 
back  to  the  earth  and  the  air  all  that  it  gathered  from 
them;  as  certainly  as  we  can  tell  that  the  lordly  city, 
whose  merchants  are  princes,  whose  dwellings  are  pal- 
aces,  whose  ships  are  on  every  sea,  shall  die,  and  the 
place  where  it  sits  in  its  majesty  shall  be  a  country  wild 
and  rude  (for  cities  have  their  time  to  fall  as  truly  as 
trees) ;  as  certainly  as  we  can  tell  when  an  eclipse  shall 
take  place,  and,  at  the  very  moment  designated  years 
beforehand,  the  shadow  commences  to  creep  over  the 
face  of  the  sun  or  moon  :  so  certainly  can  we  tell,  in 
many  respects,  what  is  the  destiny  of  this  globe  and  of 
man  dwelling  upon  it. 

The  past  is  the  certain  guide  to  the  future.  He  who 
is  best  acquainted  with  the  past  is  the  best  prepared 
to  tell  the  future;  and  that  science  which  most  clearly 
reveals  to  us  what  has  been  is  the  science  to  make 
known  to  us  what  is  yet  to  be.  That  science  is  geology. 
It  casts  a  light  upon  the  future  radiant  as  the  sun,  dis- 
pelling the  clouds  that  curtain  the  distant  land,  and 
enabling  us  to  mark  its  mountain-chains,  trace  the 
course  of  its  principal  streams,  and  observe  its  most 
prominent  features. 


LECTURES  ON  GEOLOGY.  291 

We  stand  on  the  mount  of  a  myriad  years, 

And  view  with  a  prophet's  ken 
The  course  of  this  onrushing  world  to  its  goal, 

The  fate  of  its  future  men. 

The  first  statement  that  geology  enables  us  to  make 
in  reference  to  the  future  of  this  planet  is,  that  it  will 
continue  for  millions  of  years,  as  it  has  been  in  existence 
for  millions.  While  men  believed  that  the  earth  had 
attained  its  present  maturity  in  less  than  six  thousand 
years,  it  was  not  unreasonable  to  suppose  that  it  might 
very  shortly  perish.  If  so  stately  a  tree  had  grown  to 
its  prime  in  so  short  a  time,  a  few  years  more  might 
lead  it  down  to  the  grave;  but,  when  we  learn  the 
story  of  its  mighty  past,  our  conclusion  is  very  different 
indeed. 

The  first  vegetable  forms  with  which  geology  makes 
us  acquainted  are  naked  seaweeds,  destitute  of  leaves 
and  branches ;  and  many  millions  of  years  passed  before 
exogenous  trees  adorned  the  earth,  or  fruit-trees  bore 
their  blushing  load.  The  earliest  remains  of  fishes,  as 
yet  discovered,  are  found  in  the  upper  Silurian.  They 
are  small  in  size,  and  inferior  in  organization ;  and  it  is 
not  until  we  arrive  at  the  carboniferous  period,  certainly 
millions  of  years  after  their  first  appearance,  that  we 
find  fish  developed  to  the  highest  type  of  which  fish-life 
is  capable.  The  earliest  undoubted  remains  of  reptiles 
so  nearly  resembled  fishes  in  their  structure,  that  Agas- 
siz  was  deceived  with  regard  to  their  true  character; 
regarding  them  as  fishes  instead  of  salamandroid  rep- 
tiles, or  reptiles  resembling  the  salamander.  The  skeleton 
was  somewhat  cartilaginous,  or  gristly,  while  they  belong 
to  the  batrachia,  the  lowest  order  of  reptiles.  Millions 
of  years  elapse  before  the  gigantic  ichthyosauri  float 


292  LECTURES  ON  GEOLOGY. 

upon  the  waters,  the  iguanodons  march  through  the 
forest,  the  crocodiles  crawl  along  the  shores  of  the  rivers, 
and  reptiles  attain  their  most  perfect  forms.  The  ear- 
liest  mammals  are  from  the  triassic  bed§  of  Germany, — 
small  insect-eating  marsupials,  belonging  to  the  lowest 
order  of  their  class,  and  the  most  reptilian  in  character ; 
and  millions  of  years  roll  along  through  the  oolitic, 
cretaceous,  and  tertiary  periods,  before  the  horse  scours 
the  prairie,  the  elephant  roams  through  the  jungle,  the 
cow  browses  in  the  pasture,  and  the  monkey  chatters 
in  the  tree. 

If  Nature  gave  the  fish  such  an  immense  period  of 
time  in  which  to  unfold  its  cold-blooded,  pygmy  progeny 
to  their  full  stature,  millions  of  years  to  perfect  crawling 
monsters,  and  millions  more  to  advance  beasts  from  the 
small-pouched  mammals  of  the  trias  to  the  mastodons 
and  monkeys  of  the  tertiary,  will  she  not  give  time  to 
humanity,  her  master-piece,  to  arrive  at  perfect  man- 
hood ?  Of  course,  and  time  to  enjoy  it  after  this  con- 
summation, so  much  to  be  desired,  has  been  attained. 
What  a  vast  period  this  must  necessarily  be  !  A  perfect 
man  the  world  has  yet  to  see.  Far  apart,  with  centuries 
of  barrenness  between,  noble  men  appear,  and  show  us 
the  possibilities  of  the  race  ;  but  how  few  they  are  !  We 
might  count  them  on  our  fingers,  and  then  have  digits 
to  spare,  —  so  few,  indeed,  that  we  are  ready  to  bow  down 
and  worship  them  as  gods.  What  ignorance  among  the 
scientific,  and  yet  what  pride  !  —  as  if  the  universe  had 
no  new  pages  to  be  read.  What  uricharitableness,  self- 
ishness, and  even  inhumanity,  among  the  professedly 
religious,  whose  love  is  too  often  the  offspring  of  their 
fear  !  Among  politicians,  how  few  that  are  honest  and 
true  1  Their  cry  is,  "  The  people,  the  people  !  "  but  their 


LECTURES   ON  GEOLOGY.  293 

aim,  power  and  pelf.  What  draws  the  crowd  in  a  city? 
A  monkey,  it  may  be ;  or  a  troop  of  men  who  have  made 
themselves  as  like  monkeys  as  possible  by  a  lifetime  of 
hard  training.  What  are  the  objects  of  pride  among 
civilized  men  ?  A  title,  a  ribbon,  a  cross,  a  handsome 
pipe,  or  a  fast  horse ;  among  women,  a  "  love  of  a  bon- 
net," a  splendid  mansion,  a  wealthy  husband,  or  entrance 
into  fashionable  society.  How  few  make  the  develop- 
ment of  the  mind  the  first  business  of  life  !  We  are  a 
race  of  babies,  it  must  be  confessed :  doctors,  lawyers, 
parsons,  lecturers,  princes,  presidents,  —  babies  all ! 
How  long  will  it  be  before  these  millions,  toiling,  moiling, 
like  ants  on  a  hill,  or  caterpillars  on  a  branch,  shall  be- 
come men  ?  If  a  hundred  thousand  years  at  least  have 
been  spent  in  bringing  us  to  where  we  are,  how  many 
must  be  given  to  carry  us  as  high  as  our  highest  ideal 
of  human  excellence  ?  Ages  ;  and  the  earth  shall  have 
them.  Nature  is  never  niggardly  of  time.  "Do  you 
need  a  million  years?"  she  says.  "Call  on  me,  and  fear 
not.  I  gave  them  to  the  fish,  who  never  desired  them ; 
to  the  reptile,  who  cared  not  for  them ;  to  the  beast,  who 
heeded  them  not :  how  much  more  shall  I  give  them  to 
you !  You  cannot  overdraw  at  my  bank  j  for  eternity 
is  mine,  and  all  of  it  that  is  needed  is  yours." 

Strange,  there  are  men  who  dream  that  the  course  of 
this  planet  is  nearly  run,  though  it  is  yet  so  far  from  the 
goal !  —  not  strange  either,  when  we  think  how  we  have 
neglected  Nature's  great  volume  of  instruction,  and 
listened  for  ages  to  fables.  There  has  not  been  a  year 
for  the  last  eighteen  hundred  that  many  have  not  looked 
forward  to  as  the  last  of  the  expiring  world.  Not  a 
meteor's  glare,  nor  an  earthquake  tremor,  but  is  hailed  as 
a  herald  of  coming  chaos :  and  yet  the  grand  old  earth 


294  LECTUBES  ON  GEOLOGY. 

spins  round  and  round,  carrying  these  people  along  with 
it  to  their  destiny  ;  and  so  it  will  do  for  all  their  brethren 
yet  to  be  born.  Ask  them  what  they  think  the  world 
was  made  for,  and  they  reply,  of  course,  for  the  produc- 
tion and  development  of  men;  yet,  just  as  it  commences 
to  answer  this  end,  they  anticipate  its  destruction.  A 
gentleman  selects  this  town  as  the  place  where  to  build 
a  factory  for  making  locomotives  ;  digs  deep  ;  lays  solid 
foundations,  and  rears  a  suitable  superstructure.  Within 
it  he  places  an  engine,  and  shafts  through  various  rooms 
connected  with  it :  on  the  shafts  are  drums  and  belts 
connecting  them  with  various  machines,  —  some  for  turn- 
ing, some  for  boring,  and  others  for  planing.  After 
spending  years  of  time,  hundreds  of  thousands  of  dollars, 
and  much  labor,  at  length  it  produces  tolerable  locomo- 
tives. It  takes  time  for  the  wheels  to  run  smoothly,  time 
for  the  workmen  to  execute  their  parts  with  accuracy. 
But,  just  as  this  is  in  a  fair  way  to  be  accomplished,  its 
proprietor  burns  it  to  the  ground.  What  should  we 
think  of  him  ?  We  should  charitably  conclude  that  he 
was  deranged. 

The  earth's  foundations  were  laid  deep  and  enduring 
in  the  eternity  of  the  past;  and,  after  unceasing  prepara- 
tions for  untold  ages,  the  grand  factory  for  making  men  out 
of  granite  commences  to  produce  tolerable  specimens  of 
the  race,  with  the  promise  of  vastly  better  in  the  future : 
but,  just  as  it  does  so,  these  people  believe  it  will  be 
burnt  up,  swept  with  universal  destruction,  that  it  may 
be  refitted  for  a  handful  of  "  saints,"  certainly  no  better 
than  the  average  of  their  neighbors,  who  are  to  occupy 
it  forever.  No  danger !  That  the  earth  will  cease  to 
exist  as  it  began  to  be,  there  is  no  doubt  j  but  its  end 
lies  far  away  in  the  ages  to  come,  when  its  fruit  is  ripe 
and  its  work  is  done. 


LECTURES  ON  GEOLOGY.  295 

A  tree  that  takes  twenty  years  to  arrive  at  maturity 
will  last  for  a  hundred  at  least ;  and  since  the  earth  has 
grown  during  many  millions  of  years,  as  we  now  know, 
we  may  safely  calculate  on  its  continuance  for  millions  of 
years  to  come.  Our  eyes  have  not  yet  beheld  the  whole 
of  its  surface.  Shall  our  inheritance  be  taken  from  us 
before  we  have  seen  it  ?  We  have  not  used  the  stores 
laid  up  for  us  in  the  world's  cellar  ;  nay,  we  are  finding 
new  ones  almost  every  day,  and  therefore  have  good 
reason  to  believe  that  we  have  not  yet  discovered  all  the 
treasures  prepared  for  us.  Shall  the  earth  be  destroyed 
before  we  have  received  its  gifts  or  appropriated  its 
blessings  ? 

The  world  is  a  noble  vessel,  freighted  with  a  thousand 
million  souls,  furnished  with  boundless  stores  in  her  deep 
hold,  fairly  started  for  a  distant  port,  every  sail  at  last  set, 
having  the  best  of  captains,  who  will  hardly  run  her  upoa 
a  rock  for  the  sake  of  making  a  raft  out  of  the  wreck  for 
a  handful  of  noisy  passengers,  leaving  the  rest  to  perish. 

After  we  have  decided  that  the  world  shall  endure  for 
ages,  the  question  next  arises,  What  will  be  its  future 
condition?  Is  it  the  forest  monarch,  its  trunk  rounded 
to  its  full  capacity,  its  branches  matured,  its  fruit  perfect, 
the  years  of  the  future  adding  nothing  to  its  glory  ?  or 
is  it  a  tree  with  its  heart  unknit,  its  best  branches  un- 
developed, its  beauty  unmatured,  its  fruit  imperfect, 
waiting  for  that  which  time  alone  can  bring  ? 

Old  as  geology  represents  the  world  to  be,  it  still  more 
clearly  shows  its  youth  ;  and  the  philosopher  calmly 
waits  for  its  improvement,  as  an  intelligent  parent  does 
for  that  of  his  child. 

The  world  is  young,  rny  brothers : 
We  are  all  here  in  good  tune. 


296  LECTURES  ON  GEOLOGY. 

No  man  ever  saw  the  earth  in  a  better  condition  for 
man's  occupancy  than  it  is  to-day. 

"  Abraham  saw  no  fairer  stars 
Than  those  that  burn  for  thee  and  me.'* 

Amid  the  countless  mutations  of  the  earth,  it  will  still 
march  on  to  its  great  and  glorious  destiny.  Behind  the 
eastern  hills  lie  brighter  days  than  have  yet  dawned,  and 
the  earth  shall  rejoice  in  their  glory. 

Progress  is  the  law  of  our  globe,  as  geology  abun- 
dantly testifies.  If  we  could  but  glance  at  its  history 
for  fifty  or  a  hundred  years,  we  might  doubt  it ;  but 
sweeping  over  the  ages  of  the  mighty  past,  and  con- 
trasting its  early  appearances  with  those  widely  succeed- 
ing, we  can  doubt  no  longer.  We  see  it  a  puling  infant 
in  its  fiery  cradle,  curtained  with  sulphurous  clouds; 
then  with  the  bare,  flinty  rock  for  its  floor,  and  life  as 
impossible  as  in  a  fiery  furnace,  its  air  more  poisonous 
than  the  breath  of  a  volcano,  and  its  rain  as  corrosive  as 
sulphuric  acid.  In  time,  rocks  are  ground  to  mud,  and 
the  simplest  of  plants  spread  their  rootlets  through  it  in 
search  of  nutriment.  The  air  loses  its  sulphur  and  its 
carbon,  which  are  stored  away  for  distant  uses.  The 
water  becomes  purer,  and  all  elements  better  fitted  for 
the  development  and  sustentation  of  life,  which  advances 
from  the  seaweed  to  the  cedar,  the  wheat,  and  the  rose- 
bush ;  from  the  unsensitive  radiate,  through  mollusk,  fish, 
reptile,  bird,  and  mammal,  to  intelligent  man.  If  the 
world  has  thus  improved  in  the  past,  what  more  reason- 
able than  that  it  shall  continue  to  improve  in  the  future? 
If  it  has  marched  with  such  an  unfaltering  step  in  the 
pathway  of  progress  for  such  an  immense  period,  who 


LECTURES  ON  GEOLOGY.  297 

can  doubt  that  it  will  continue  so  to  do?  Why  should 
progress  cease  at  this  period  in  the  world's  history  ?  If 
there  was  any  reason  for  improvement  when  there  was 
nothing  to  behold  it  but  the  leaden  eye  of  the  fish,  or  to 
care  for  it  but  the  dull  reptile,  how  much  more  reason 
now  that  man  is  here,  eagerly  watching  every  advance, 
his  happiness  increasing  at  every  step  of  its  progress ! 

Not  only  does  the  knowledge  of  the  past  that  geology 
gives  enable  us  to  predict  the  general  improvement  of 
the  earth  as  man's  abode,  but  by  it  we  can  indicate  more 
particularly  the  direction  that  this  improvement  will 
take.  First,  volcanoes  will  die,  and  earthquakes  cease. 
The  outpourings  of  fiery  matter  from  volcanoes,  and  the 
convulsive  shakings  of  the  ground,  are  among  man's 
greatest  troublers :  they  are  constant  sources  of  appre- 
hension to  those  who  live  in  neighborhoods  subject  to 
them ;  and  those  who  have  been  most  familiar  with  them 
regard  them  with  the  greatest  horror.  No  country  is 
exempt  from  their  influence,  and  their  consequences  are 
sometimes  most  disastrous.  In  the  year  526,  as  many 
as  two  hundred  and  fifty  thousand  persons  perished  at 
Antioch ;  and,  seventy-six  years  afterward,  a  second  earth- 
quake destroyed  sixty  thousand.  In  1692,  seventy-four 
thousand  persons  lost  their  lives  at  Messina;  and  in 
Quito,  in  1797,  forty  thousand.  It  is  estimated  that 
thirteen  millions  of  the  human  race  have  thus  perished 
On  an  average,  there  is  an  earthquake  every  eight 
months  that  is  destructive  to  human  life ;  and  of  smaller 
and  harmless  ones,  a  shock  somewhere  every  day.  Yet 
how  solid  the  earth  is  to-day,  compared  with  what  it 
once  was !  The  rents,  crevices,  and  veins  which  seam 
the  rocks  in  millions  of  places,  their  sides  often  made 
smooth  as  glass  by  rubbing  against  each  other  as  the 


298  LECTURES  ON  GEOLOGY. 

rocks  have  been  elevated  and  depressed,  tell  a  story  of 
the  past  world,  in  contrast  with  which  the  present  seems 
peaceful  and  stable. 

There  was  a  time,  without  doubt,  when  the  earth  was 
a  volcanic  globe,  its  boiling  lava  forming  a  shoreless 
sea  of  fire.  Long  after  this,  volcanoes  must  have  covered 
its  surface  as  blisters  do  the  slag  of  an  iron  furnace  ; 
its  face  pitted  and  scarred  as  the  moon's  is  to-day,  or 
a  man's  marked  by  the  small-pox ;  while  the  thin  crust 
was  in  continual  motion  by  the  internal,  heaving  tides. 
Ages  passed,  and  the  rocks  thickened,  the  numerous 
craters  were  obliterated  or  buried,  earthquakes  less  fre- 
quently rent  it,  and  comparative  peace  and  order 
reigned.  New  England,  now  so  quiet,  was  once  shaken 
and  convulsed,  seamed  and  rent :  enormous  crevices 
poured  out  glowing  rivers,  that  licked  up  lakes  and 
inland  seas  with  fiery  tongue,  leaving  marks  that  tell  to 
the  geologist  of  these  desolations  of  an  early  time. 
The  volcanoes  and  earthquakes  of  the  present  are  but 
the  puny  offspring  of  a  once  mighty  host;  and  are 
destined,  like  them,  to  expire.  While  active  volcanoes 
are  numbered  by  tens,  extinct  ones  are  numbered  by 
thousands.  In  New  Zealand,  there  are  sixty  extinct 
volcanoes  within  a  radius  of  ten  miles ;  thousands  in 
Italy  and  Central  France ;  some  of  them  much  larger 
than  any  active  ones. 

Day  by  day,  the  world  is  cooling ;  radiating  its  heat, 
into  space  through  its  thick  crust ;  sending  it  out 
through  volcanic  vents  and  hot-springs.  Its  rocky  ribs 
increase  in  thickness  and  strength  continually ;  and  the 
time  must  come,  however  distant  it  may  be,  when  the 
last  earthquake  shall  give  its  last  heave,  and  lie  down  in 
its  rocky  den,  and  expire,  —  when  the  last  volcano  shall 


LECTURES   ON   GEOLOGY. 

send  out  its  last  smoky  puff.  No  more  shall  the  dwellers 
near  Vesuvius  and  JEtna  look  up  with  terror  to  the 
mountain,  or  shake  with  dread  at  the  midnight  hour  aa 
they  listen  to  the  subterranean  thunder.  Men  will 
plant  vine-yards  and  olive-yards  to  their  summits ;  de- 
scend into  their  craters,  and  make  orchards  ;  and  young 
men  and  maidens  shall  dance  in  the  moonlight,  in  the 
socket  of  the  blind  volcano's  eye. 

The  past  history  of  the  globe  furnishes  indications 
that  useless  and  troublesome  plants  will  disappear,  and 
seeds  and  fruits  previously  unknown  shall  bless  the 
future  dwellers  on  the  earth.  During  the  carboniferous 
period,  the  land-surface  of  the  earth  was  a  wilderness 
of  weeds,  rushes,  ferns,  horse-tails,  club-mosses,  every- 
where ;  but  no  grass,  no  grain,  and  probably  no  edible 
fruit:  the  produce  of  a  million  acres  would  not  have 
furnished  a  man  with  a  breakfast.  Where  are  the  giant 
weeds  of  this  olden  time  and  of  times  long  subsequent? 
All  vanished.  As  conditions  improved,  vegetation  im- 
proved ;  higher  forms  appeared  ;  inferior  forms  died  out : 
arid  the  means  by  which  this  was  accomplished  exist 
and  operate  to-day,  —  our  new  and  improved  varieties  of 
plants  are -evidences  of  it, —  and  will  improve  the  plants 
of  the  future.  Noxious  weeds  shall  thus  disappear,  and 
fruits  that  neither  we  nor  our  fathers  have  known  shall 
take  their  place. 

The  world  is  now  infested  with  lions,  tigers,  leopards, 
hyenas,  bears,  crocodiles,  boa-constrictors,  vipers,  rattle- 
snakes, and  other  poisonous  reptiles,  destroying  human 
beings  and  their  domestic  animals.  Whole  villages  in 
India  have  been  depopulated  by  the  ravages  of  the 
tiger ;  lions  are  the  dread  of  man  in  many  and  largo 
districts  of  country  ;  and  we  are  acquainted  with  nearly 


300  LECTURES  ON  GEOLOGY, 

sixty  species  of  poisonous  shakes.  In  consequence  of 
these,  the  sum  total  of  human  enjoyment  is  much  de- 
creased. There  is  great  room  for  improvement  in  this 
direction  ;  and  it  will  come.  Had  a  man  been  dropped 
upon  our  planet  during  the  oolitic  period,  he  would  but 
have  served  as  a  mouthful  for  some  of  the  huge  carniv- 
orous crawlers  with  which  the  world  then  abounded. 
Where  are  the  monstrous  lizards  of  the  Wealden,  the  sight 
of  whose  mere  skeletons  makes  us  shudder?  Where 
are  the  cave  lions  that  once  prowled  through  the  woods 
of  Great  Britain,  the  cave  tigers  that  hunted  by  their 
side,  and  the  cave  hyenas  that  munched  the  bones  that 
have  been  found  in  European  caves?  As  the  world 
became  prepared  for  higher  beings,  it  became  less  fitted 
for  them,  and  they  perished.  The  crocodiles  of  to-day 
are  the  puny  representatives  of  the  huge  saurians  of 
the  reptile  age ;  and  the  diminutive  lions  and  tigers 
of  to-day,  never  seen  in  Europe,  save  harmlessly  caged 
in  the  travelling  caravan,  are  the  degenerate  kindred  of 
the  ferocious  cave  dwellers  of  the  post-pliocene  times. 
So,  in  the  time  to  come,  those  that  remain  shall  die  ;  and 
in  the  language  of  Isaiah  we  may  prophesy,  "  No  lion 
shall  be  there,  neither  shall  any  ravenous  beast  go  up 
thereon  :  it  shall  not  be  found  there."  "  There  shall  be," 
so  far  as  these  are  concerned,  "  nothing  to  hurt,  and  noth- 
ing to  destroy." 

Noxious  insects  must  likewise  disappear.  Geologists 
know  comparatively  little  about  the  insect  inhabitants  of 
the  ancient  world ;  but  with  a  tropical  climate  every- 
where, swampy  lands,  and  rank  vegetation,  there  must 
have  been  clouds  of  noxious  insects,  and  of  large  size. 
From  my  own  investigations,  I  know  that  our  gnats  an-1 
mosquitoes,  our  tarantulas  and  scorpions,  are  but  a  feeb:^ 


LECTURES   ON  GEOLOGY.  301 

few  that  represent  the  perished  hosts  of  the  tertiar}r  and 
earlier  times.  Those  that  remain  must  in  like  manner 
perish ;  for  the  world  is  for  man,  and  whatever  wars  with 
his  highest  well-being  must  disappear. 

The  land-surface  of  the  earth  will  be  greatly  increased. 
At  present,  the  land-surface  of  the  globe  is  said  to  be 
only  about  three-elevenths  of  the  whole ;  and  the  fish 
possess  vastly  more  than  the  men.  But  there  was  a  time 
in  the  early  history  of  the  earth,  when  water  covered 
nearly,  if  not  entirely,  its  whole  face.  During  the  Silu- 
rian period,  we  know  that  the  land-surface  was  composed 
of  but  a  few  craggy  islands,  germs  of  the  mighty  con- 
tinents that  now  exist.  During  the  Devonian  period, 
the  islands  were  expanded,  and  many  united.  In  the 
time  of  the  coal-measures,  continental  areas  were  devel- 
oped ;  but,  even  then,  more  than  half  of  North  America 
lay  beneath  the  waves.  The  succeeding  formations  in- 
dicate longer  and  broader  territory.  Higher  and  higher 
rose  the  mountains,  and  the  waters  of  the  ocean  retired. 

Not  only  does  the  land-surface  of  the  globe  increase 
in  consequence  of  its  elevation,  as  I  have  shown  in 
former  lectures,  but,  as  the  earth  cools,  the  water  on  its 
surface  descends  to  greater  depths,  circulates  through 
its  crevices,  and  becomes  a  constituent  of  the  rocks  that 
compose  its  crusts,  not  excepting  the  hardest:  some 
rocks  contain  even  as  much  as  twenty-five  per  cent. 
There  was  a  time  when  the  water  of  the  globe  was  kept 
in  the  atmosphere  by  its  intense  heat ;  then  a  time  when  it 
rested  upon  its  surface :  and,  even  now,  it  does  not  de- 
scend more  than  two  or  three  miles  at  the  farthest ;  for 
at  that  depth  it  would  be  converted  into  steam.  But, 
as  ages  pass  away,  the  distance  to  which  it  can  descend 
will  increase  ;  the  superfluous  waters  of  the  globe  will  be 


302  LECTUEE8  ON  GEOLOGY. 

drained  off,  and  a  much  larger  extent  of  land-surface  be 
produced  for  man's  occupancy. 

It  is  a  common  opinion  that  the  cooling  process,  by 
which  volcanoes  and  earthquakes  are  to  be  destroyed, 
will  produce  such  a  diminution  of  the  heat  of  the  globe, 
that  life  will  eventually  be  entirely  destroyed  in  conse- 
quence of  the  extreme  cold.  It  is  true,  there  was  a 
time  when  the  temperature  of  the  earth  was  extra 
tropical,  even  to  the  poles;  but  during  the  drift  period, 
which  probably  lasted  for  hundreds  of  centuries,  w*e 
know  that  the  cold  was  so  great  in  Europe,  that  Switzer- 
land, Eastern  France,  and  Northern  Italy,  were  covered 
with  a  sheet  of  ice  of  enormous  size  and  thickness, 
slowly  moving  over  the  land.  The  cold  was  so  intense 
in  North  America,  that  a  corresponding  icy  sheet 
covered  it,  extending  from  the  Arctic  Ocean  as  far  south 
as  Southern  Massachusetts,  Southern  Ohio,  and  Northern 
Kansas ;  narrowing  as  it  approached  the  western  side 
of  the  continent,  as  the  marks  made  by  its  motion,  and 
still  remaining,  clearly  testify.  Gradually  the  domain 
of  Winter  has  been  diminished,  his  stern  rigor  relaxed  ; 
and  wide  realms  have  been  delivered  from  his  grasp. 
Even  within  the  historical  period,  there  seems  to  have 
been  some  climatal  change  in  this  direction.  In  the 
time  of  Strabo,  the  vine,  it  is  said,  could  not  be  grown 
in  Northern  France ;  and  the  Rhine  and  the  Danube 
were  frequently  frozen  over.  At  the  present  time,  the 
vine  is  not  only  grown  all  over  France,  but  even  to  the 
north  of  it ;  and  the  Rhine  and  the  Danube  are  very 
rarely  frozen.  It  may  be  that  the  vine  has  become 
acclimated  to  a  colder  region  since  the  time  of  Strabo, 
and  that  the  accounts  of  ice  on  the  Rhine  and  Danube 
are  exaggerated.  The  amelioration  of  climate  within  the 


LECTURES  ON  GEOLOGY.  303 

historical  period  may  have  been  too  slight  to  be  recog- 
nized ;  but  geology  enables  us  to  grasp  such  immense 
periods,  that  we  can  draw  our  conclusions  with  confi- 
dence. It  is  not  so  hot  as  it  once  was ;  it  is  not  so  cold : 
in  both  respects,  the  climate  of  a  large  part  of  the  earth 
has  improved.  Even  since  the  time  of  the  stone  men 
of  the  Valley  of  the  Somme,  when  bowlders  were  floated 
down  that  river  on  ice,  the  climate  of  France  has  become 
much  warmer ;  and  we  may  fairly  conclude,  that,  notwith- 
standing the  decrease  in  the  earth's  internal  heat, — • 
which,  if  entirely  absent,  could  not  materially  affect  the 
external  temperature,  —  the  climate,  by  the  operation  of 
unknown  agencies,  is  slowly  becoming  modified,  and  the 
world  better  adapted  to  the  necessities  of  mankind. 

If,  however,  these  various  improvements  should  not 
take  place  by  the  operation  of  natural  forces,  they  may 
be  effected  by  the  instrumentality  of  man.  For  ages, 
the  earth  was  modified  by  inorganic  agencies ;  then  un- 
consciously modified  by  the  animals  and  plants  living 
upon  it :  now  it  is  being  consciously  modified  by  man, 
and  will  be  much  more  so  in  the  future.  The  earth  was 
first  fire-made,  rude  as  the  shapeless  mass  of  iron  drawn 
from  a  puddling  furnace,  and  placed  under  the  forma- 
tive hammers ;  next  water-made,  the  face  of  the  earth 
washed,  the  fire-made  rocks  ground  down,  layer  after 
layer  of  sediment  deposited,  and  the  metamorphic  foun- 
dations securely  laid.  It  was  subsequently  shell-made, 
plant-made,  beast-made,  and  is  now  to  be  man-made, 
finished,  and  beautified.  The  savage,  like  the  beasts 
that  preceded  him,  knew  not  the  work  that  was  given 
him  to  do ;  but  now  we  are  learning  the  full  significance 
of  our  mission  in  this  direction,  and  our  constantly-in- 
creasing intelligence  is  being  used  to  bring  the  earth 


304  LECTURES  ON  GEOLOGY. 

into  the  best  possible  condition  to   administer   to  our 
happiness. 

If  volcanoes  do  not  die  out  and  earthquakes  cease  by 
the  operation  of  causes  distinct  from  man's  agency,  they 
may  yet  be  brought  to  an  end  by  that  agency,  or  their 
destructive  force  confined  to  such  portions  of  the  globe 
as  he  may  determine.  At  one  time,  the  lightning  flashed 
at  will,  and  no  man  in  the  presence  of  a  thunder-storm 
could  feel  secure  from  the  deadly  bolt ;  and,  a  hundred 
years  ago,  he  would  have  been  a  bold  prophet  who 
should  have  foretold  that  man  would  obtain  the  mastery 
over  this  destructive  manifestation  of  electricity  that 
we  now  possess,  and  bring  down  its  vengeful  fires  on  a 
slender  rod  in  safety  to  the  ground.  The  future  shall 
do  infinitely  more  for  man  than  the  past  has  done  ;  for 
our  ability  increases  with  every  step  that  we  take,  and 
that  becomes  easy  to-day  which  seemed  absolutely  im- 
possible yesterday.  The  more  dangerous  any  force  is 
that  we  have  not  mastered,  the  more  useful  it  becomes 
when  we  have  reduced  it  to  obedience.  Some  method 
may  be  discovered  by  which  the  terribly  destructive 
agent  engendered  in  the  earth's  interior,  arid  manifesting 
itself  in  volcanoes  and  earthquakes,  may  be  transmitted 
quietly  and  safely  into  space  after  yielding  its  giant 
force  for  man's  benefit.  Marsh  tells  us,  in  his  "  Man  and 
Nature/'  that  "  it  is  a  very  ancient  belief  that  earthquakes 
are  more  destructive  in  districts  where  the  crust  of  the 
earth  is  solid  and  homogeneous  than  where  it  is  of  a 
looser  and  more  interrupted  structure.  Aristotle,  Pliny 
the  elder,  and  Seneca,  believed  that  not  only  natural 
ravines  and  caves,  but  quarries,  wells,  and  other  human 
excavations,  which  break  the  continuity  of  the  terres- 
trial strata,  and  facilitate  the  escape  of  elastic  vapors, 


LECTURES  ON  GEOLOGY.  305 

have  a  sensible  influence  in  diminishing  the  violence 
and  preventing  the  propagation  of  the  earth-waves.  In 
all  countries  subject  to  earthquakes,- this  opinion  is  still  < 
maintained  ;  and  it  is  asserted,  that,  both  in  ancient  and 
in  modern  times,  buildings  protected  by  deep  wells  un- 
der or  near  them  have  suffered  less  from  earthquakes 
than  those  the  architects  of  which  have  neglected  this 
precaution.'7  Our  ability  to  penetrate  the  earth's  crust 
increases  every  day ;  and  by  numerous  deep  wells  we 
may  bring  up  harmlessly,  and  usefully  employ,  what  is 
now  the  cause  of  such  dire  calamities.  When  earth- 
quake-power drives  our  machinery,  the  holiday  of  the 
world  will  have  come. 

Nearly  all  active  volcanoes  are  in  the  vicinity  of  the 
ocean :  as  Vesuvius,  near  the  Bay  of  Naples  ;  ^Btna,  on 
the  Island  of  Sicily,  and  close  to  the  Mediterranean.  Of 
the  two  hundred  and  twenty-five  active  volcanoes,  one 
hundred  and  fifty-five  are  situated  on  islands ;  and  this 
suggests  the  method,  as  well  as  the  possibility,  of  their 
extinction  by  man's  agency.  The  sea  has  already  ex- 
tinguished thousands,  —  ay,  millions  ;  and  the  time  may 
come  when  man  shall  apply  this  extinguisher  to  the  still 
remaining  fires,  and  volcanoes  will  be  felt  and  feared  no 
more.  We  have  men  in  New  England  who  would  under- 
take to  make  a  tunnel  into  the  heart  of  Vesuvius,  and 
let  in  the  Mediterranean,  and  accomplish  it  too ;  and, 
however  difficult  such  tasks  may  appear  now,  every 
year  makes  them  easier. 

If  noxious  weeds  should  still  continue  to  grow,  with 
no  apparent  natural  diminution  of  their  numbers,  man 
will  say  to  them,  "  Begone  ! "  and  they  will  disappear. 
When  Australia  was  first  discovered,  there  were  no 
plants  worthy  of  cultivation  on  the  island,  and  no  fruit 
20 


306  LECTURES  ON  GEOLOGY. 

• 

that  man  could  use  to  benefit  except  two  or  three  sour 
berries.  All  the  vegetable  productions  were  weeds ; 
that  is,  plants  unserviceable  to  man.  But  intelligent 
labor  has  made  a  wonderful  change.  "  Oranges,  pine- 
apples, figs,  bananas,  grapes,  mulberries,  peaches,  necta- 
rines, alligator-pears,  and  guavas  flourish  side  by  side 
with  wheat,  corn,  potatoes,  and  all  the  fruits,  flowers, 
and  vegetables  of  the  temperate  zone;"  and  the  weeds 
have  disappeared,  that  these  might  take  their  place. 

"  In  China,  with  the  exception  of  a  few  water-plants 
in  the  rice-grounds,  it  is  sometimes  impossible  to  find  a 
single  weed  in  an  extensive  district ;  and  the  late  emi- 
nent agriculturist,  Mr.  Coke,  is  reported  to  have  offered 
in  vain  a  considerable  reward  for  the  detection  of 
a  weed  in  a  large  wheat-field  on  his  estate  in  Eng- 
land."* The  time  will  come  when  man  shall  possess 
the  earth,  and  determine  what  plants  shall  grow  upon  it, 
as  our  best  farmers  and  gardeners  do  on  their  lands; 
and,  when  that  time  comes,  the  day  of  thorns  and  thistles, 
and  all  troublesome  weeds,  will  be  forever  over. 

In  like  manner,  destructive  beasts,  poisonous  reptiles, 
and  noxious  insects,  shall  be  extirpated  by  man,  if  they 
do  not  disappear  by  such  a  natural  process  of  extinction 
as  has  swept  away  the  megalosaurus  of  the  oolite  and 
the  cave  tiger  of  more  recent  times.  The  rifle  has 
proved  the  master  of  the  lion,  and  it  rapidly  disappears 
before  the  advance  of  civilization.  In  India,  they  are 
now  confined  to  a  few  wild  portions ;  and,  in  South 
Africa,  they  have  vanished  from  all  the  fully-settled 
districts.  Wolves  and  bears  were  quite  common  in 
Great  Britain  since  the  Christian  era,  but  were  ?xtir 

*  Mail  and  Nature  '.  Marsli. 


LECTURES  ON  GEOLOGY.  307 

pated  in  England  in  1350  ;  in  Scotland,  about  1600  ;  and 
in  Ireland,  about  1700.  The  more  numerous  and  intel- 
ligent the  people,  the  sooner  they  obtain  dominion 
over  these  foes.  Lions  and  bears  existed  in  Judaea  in 
scriptural  times.  Panthers,  wild-cats,  rattlesnakes,  and 
copperheads  abounded  in  the  Middle  and  many  of  the 
Northern  States,  where,  at  the  present  time,  they  are 
hardly  ever  seen.  Where  intelligent  man  goes,  the  bear 
retreats,  growling,  to  the  wilderness.  The  rattlesnake 
finds  more  danger  in  the  glance  of  his  eye  than  man 
does  in  its  fangs ;  and,  when  man's  dominion  over  the 
earth  is  complete,  these  destroyers  of  his  peace  will 
exist  no  longer. 

Serpents  are  most  numerous,  and  most  poisonous, 
where  man  is  least  developed.  Taking  the  general 
average,  about  one  in  five  is  poisonous;  but,  in  Africa, 
one  out  of  every  three,  and  in  Australia  as  many  as 
seven  out  of  ten,  are  poisonous.  Intelligence  has  slain 
the  most  deadly.  Who  can  doubt  the  extinction  of  the 
remaining,  when  the  heirs  of  the  world  shall  obtain 
their  inheritance  ? 

Mosquitoes  and  gnats  are  terrible  pests  of  human 
kind,  sucking  out  a  man's  blood  and  patience  at  the 
same  time.  In  some  localities  in  South  America,  the 
wretched  inhabitants,  to  save  themselves  from  the  at- 
tacks of  these  pests,  sleep  with  their  bodies  covered 
over  with  sand  three  or  four  inches  deep  ;  the  head  only 
being  left  out,  and  covered  with  a  cloth.  In  some  of 
the  densely-wooded  and  swampy  districts  of  Canada,  I 
have  seen  the  necks  of  the  men  and  boys,  working  in 
the  woods,  swollen  and  bloody  from  the  attacks  of  a 
small  gnat,  which  renders  a  veil  necessary  for  those 
who  wish  to  avoid  its  painful  bite.  These  troublesome 


308  LECTURES  ON  GEOLOGY. 

insects  are  bred  in  stagnant  water;  and,  when  the  \vuter 
is  made  to  run,  they  will  run  also :  when  a  country  is 
thoroughly  opened  and  drained,  their  ravages  cease. 
Neighborhoods  once  infested  by  them  are  now  nearly 
free  from  their  attacks ;  and  those  now  cursed  are  but 
waiting  for  man's  intelligent  voice  to  bid  the  plague  to 
cease. 

Should  the  climate  remain  cold  and  inhospitable  in 
winter,  as  at  present,  we  shall  then  make  an  artificial 
climate  better  suited  to  our  necessities,  and  more  in 
harmony  with  our  comfort.  This,  we  may  be  told,  is 
impossible :  so  once  appeared  what  we  have  already 
accomplished. 

There  was  a  time  when  man  never  dreamed  of  warm- 
ing himself,  or  preparing  his  food,  by  artificial  heat.  He 
pulled  up  the  wild  roots,  picked  the  wild  fruits,  and 
swallowed  the  raw  oysters  and  mussels  as  he  wandered 
naked  along  the  beach.  A  cave  by  the  river-side,  or  a 
hollow  tree,  served  him  for  a  habitation ;  and  here  he  crept 
when  the  winter  storm  blew,  and  lay  like  a  wild  beast 
in  his  lair  till  the  warm  breath  of  spring  wakened  him, 
gaunt  and  hungry,  to  life  once  more.  Ages  passed  before 
he  learned  to  make  a  fire  and  feed  it;  make  a  tent  of 
skins,  and  warm  it  by  a  fire  in  the  centre.  By  slow 
steps,  he  passed  from  rude  tents,  and  ruder  caverns  in 
the  ground,  to  stone  huts,  cabins,  comfortable  houses, 
and  stately  mansions,  with  a  heating  apparatus  by  which 
winter  is  shorn  of  his  rigor,  and  a  genial  temperature 
surrounds  us  continually.  By  what  possibility  could  a 
thousand  North-American  Indians  have  met  together 
in  council  in  the  month  of  January,  with  the  thermome- 
ter at  zero?  How  easily  we  manage  it!  There  is  an 
iron  box :  we  put  into  it  coal  from  our  Pennsylvania 


LECTURES  ON  GEOLOGY.  309 

mines ;  take  out  the  heat  that  it  took  in  from  the  sun- 
shine when  it  was  growing,  vegetable  matter ;  diffuse  it 
through  the  room,  and  snap  our  fingers  at  the  frost;  for 
we  have  made  a  climate  to  suit  ourselves. 

What  we  have  learned  to  do  for  ourselves  we  shall 
some  day  learn  to  do  for  our  plants,  and  render  ourselves, 
in  a  great  measure,  independent  of  the  exterior  climate. 
Here  and  there  the  work  has  been  commenced,  on  a 
small  scale,  in  the  shape  of  green  and  hot  houses.  These 
show  us,  and,  still  more,  the  Crystal  Palace  of  Sydenham, 
and  the  Garden  of  Plants  in  Paris,  how  flowers  can  be 
made  to  bloom,  birds  to  sing,  and  butterflies  and  bees 
give  a  summer-like  appearance  to  grounds,  while  Winter 
holds  in  his  stern  embrace  all  surrounding  lands.  Why 
should  the  land,  from  which  all  our  food  is  derived, 
either  at  first  or  second  hand,  lie  idle  for  six  months 
in  the  'year,  and,  in  some  parts  of  the  country,  for 
eight?  There  is  sand  enough  in  New  England  alone' to 
make  glass  enough  to  cover  the  whole  of  North  America, 
from  the  fortieth  parallel  of  latitude  to  the  Polar  Sea ; 
there  is  iron-ore  enough  to  make  iron  sufficient  to  sup- 
port it,  and  thus  enclose  the  whole  land ;  at  the  same 
time,  deficient  as  New  England  is  in  fuel,  there  is  fuel 
enough  to  give  a  summer  heat  in  the  depth  of  winter  to 
her  entire  domain. 

But  fuel,  even  now,  is  scarce  and  dear,  and  the  moder- 
ate use  of  fires  to  warm  our  dwellings  taxes  our  powers. 
How,  then,  shall  we  heat  the  whole  land  ?  Wood,  of 
course,  must  make  way  for  coal ;  and  this,  as  its  use  in- 
creases, will  diminish  in  price.  The  American  coal-cellar 
is  well  supplied ;  and,  for  a  long  time  to  come,  we  shall 
draw  from  what  some  have  designated  "  exhaustless  re- 
Bources."  They  are  not,  however,  exhaustless.  The 


310  LECTURES  ON  GEOLOGY. 

coal  of  England  is  going  at  the  fearful  rate  cf  eighty 
million  tons  a  year,  or  six  square  miles  of  an  average 
thickness  of  six  feet ;  and  already  the  question  of  fuel 
in  the  future  has  assumed  a  great  importance  in  Eng- 
land. Our  evil  day  will  only  be  retarded  ;  and,  eventually, 
we  must  answer  the  same  question.  We  are,  however, 
now  in  a  condition,  or  at  least  approaching  a  condition, 
that  suggests  an  answer.  Our  oil  discoveries  have 
much  diminished  the  importance  of  this  question  to  us, 
drawing  out  of  the  earth,  as  we  now  do,  a  million  gallons 
of  petroleum  a  day.  "But  will  not  the  oil  give  out?" 
Of  course,  in  time ;  but  that  time  is  far  distant.  The 
oil-bearing  rocks  are  of  great  thickness,  and  of  vast  ex- 
tent. From  the  base  of  the  Silurian  formation  to  the 
top  of  the  Devonian,  is,  we  now  know,  veritable  oil 
territory ;  the  oil-bearing  corals  being  found  in  all  the 
limestones  of  these  formations.  As  these  rocks  underlie 
fully  one-half  of  the  continent,  the  possible  oil-ground  is 
of  immense  extent.  The  gas-springs  of  Western  New 
York  indicate  its  existence  there,  though  probably  at 
great  depth.  New  England  may  yet  count  it  among  her 
treasures  ;  and,  when  we  bore  for  it  to  depths  of  four  or 
five  thousand  feet,  we  shall  find  deposits  large  and  en- 
during, of  which  few  at  the  present  time  dream.  We 
shall  burn  it  for  fuel  as  well  as  for  illumination ;  steam- 
boats will  cross  the  ocean  by  its  aid,  and  locomotives  run 
more  swiftly  and  with  greater  ease  and  cheapness  than 
before.  This  is  a  new  servant  that  man  has  wakened 
from  the  sleep  of  ages ;  and  we  are  but  beginning  to 
learn  his  powers,  and  their  appplication  to  the  supply  of 
our  needs.  Nor  does  the  amount  of  free,  flowing  oil, 
give  us  any  idea  of  the  immense  amount  of  this  material 
which  the  earth  contains.  Manv  limestones  and  sand* 


LECTURES  ON  GEOLOG?.  311 

stones  are  so  saturated  with  oil,  that  it  can  be  distilled 
from  them  with  profit.  Bituminous  shales  abound,  from 
one  ton  of  which  from  twenty  to  sixty  gallons  of  oil  may 
be  distilled.  I  saw  one  bed  of  petroleum  shale,  partly 
in  Utah,  and  partly  in  Colorado,  that,  on  a  moderate  com- 
putation, contained  forty  thousand  million  barrels  of  oil. 
A  bed  of  bituminous  shale,  thirty  feet  thick,  underlies 
one-half  of  Tennessee,  and  contains  much  more  oil  even 
than  this. 

"  But  the  oil  will  not  last  forever."  True  :  we  shall 
drain  the  land  of  oil  as  surely  as  England  will  exhaust 
her  cellars  of  coal ;  and  the  question  arises,  What  shall 
we  do  then  ?  The  earth  is  a  great  magazine  of  fire,  arid 
man  will  yet  draw  from  it  for  his  benefit.  The  Garden 
of  Plants  in  Paris  is  heated  by  water  from  an  artesian 
well  eighteen  hundred  feet  deep,  which  has  a  tempera- 
ture of  eighty -two  degrees  Fahrenheit,  and  is  carried  in 
pipes  under  the  soil.  A  salad  ground  at  Erfurt,  in 
Saxony,  heated  by  water  from  an  artesian  well,  yields  a 
profit  of  sixty  thousand  dollars  a  year  to  the  proprietor. 
These  are  indications  of  the  applications  yet  to  be  made 
of  the  interior  heat  of  the  earth.  Shafts  are  sometimes 
sunk  now  to  a  depth  of  two  thousand  feet ;  and  it  would 
be  possible  to  bore  from  the  bottom  of  those  to  a  farther 
depth  of  four  thousand  feet :  at  that  depth,  we  should 
find  a  heat  of  at  least  one  hundred  and  fifty  degrees ; 
and  in  some  cases,  by  striking  deep  crevices,  we  should 
obtain  a  much  greater  heat  than  this. 

Many  hot  springs  are  located  on  crevices  which  de- 
scend to  such  great  depths  that  the  high  temperature  of 
the  earth's  interior  gives  heat  to  their  waters,  and  thus 
we  may  learn  how  to  avail  ourselves  of  this  grand  source 
of  heat  and  power.  For  ages  the  savage  knew  not  that 


312  LECTURES  ON  THEOLOGY. 

the  possibility  of  heat  existed  in  the  tree  under  whose 
shelter  he  lay. 

By  boring  to  a  depth  of  a  mile  and  a  half  (which  is, 
perhaps,  not  impossible  in  the  present  condition  of  the 
mechanical  arts,  and  may  be  easily  accomplished  in  the 
future),  we  should  have  boiling  water,  supposing  we  had 
an  artesian  well,  which  we  should  probably  have  every- 
where, at  that  depth.  The  steam  that  must  exist  there 
would  be  sufficient  to  drive  up  the  water  with  great 
force ;  so  that,  in  many  cases,  mechanical  power  could  be 
derived  from  it  as  well  as  from  the  steam  itself.  The 
heated  water  from  these  wells  could  be  carried  into  our 
houses,  warming  them  most  readily  and  economically. 
On  a  cold  winter's  morning  we  could  turn  on  the  hot 
water  or  steam,  and  supply  ourselves  with  summer's 
heat  without  leaving  our  beds.  It  could  be  applied  to 
cooking  without  difficulty,  and  supply  the  largest  por- 
tion of  the  needs  that  wood  and  coal .  but  inadequately 
and  expensively  supply  at  the  present  time.  Laid  under 
the  soil,  protected  by  glass,  we  should  have  a  summer's 
heat  supplied  to  our  growing  plants  in  winter,  and  bring 
the  benefits  of  the  tropics  to  our  doors.  Not  only  could 
we  produce  crops  the  whole  year,  but  we  might  have  in 
New  England  not  only  the  apple,  pear,  plum,  and  peach, 
but  the  orange,  fig,  date,  lemon,  and  pine-apple  by  their 
side. 

I  :Sx  no  time  for  these  things  to  come  to  pass  :  it  may 
be  c^e  thousand  or  ten  thousand  years.  It  has  taken  an 
immense  period  since  man  came  into  existence  to  ad- 
vance to  our  present  position,  and  much  time  will  be 
necessary  to  take  us  where  we  are  destined  to  go  j  but 
he  who  can  judge  of  the  tree  by  the  sapling  may  know 
that  these  things  shall  be. 


LECTURES  ON  GEOLOGY.  313 

"  But  suppose,  that,  in  time,  the  earth  should  bee  >me 
cold  to  a  great  depth,  so  that  no  more  heat  could  be  ex- 
tracted from  it  by  man :  what  then  ?  "  Even  then  we 
should  not  despair.  Water,  antagonistic  as  it  is  to  fire, 
can,  nevertheless,  furnish  us  with  the  means  to  produce 
it.  Water,  as  we  know,  is  composed  of  oxygen  and 
hydrogen  gases,  in  the  proportion  of  eight  parts,  by 
weight,  of  oxygen,  to  one  of  hydrogen ;  and  these  gas- 
es can  be  produced  from  water  by  several  methods.  If 
the  ends  of  the  platinum  wires  connected  with  a  gal- 
vanic battery  be  placed  near  each  other  in  a  vessel  of 
water,  bubbles  of  hydrogen  will  rise  from  the  one,  and 
of  oxygen  from  the  other:  the  water  is  decomposed,  and 
its  constituent  gases  are  thus  produced.  Hydrogen  is 
a  very  inflammable  gas,  and  oxygen  is  the  supporter  of 
combustion ;  and  when  united,  as  in  the  oxy-hydrogen 
blowpipe,  they  produce  the  most  intense  artificial  heat. 
Platinum,  which  does  not  melt  in  the  hottest  furnace, 
fuses  in  the  heat  of  this  like  wax.  In  water,  then,  we 
have  stored  up  fuel  for  ages  unnumbered.  Our  present 
methods  of  obtaining  it  are  too  expensive  for  ordinary 
use ;  but  who  can  doubt  that  man's  constantly-increasing 
ingenuity  will  invent  some  easy  method  of  separating 
these  valuable  gases,  and  thus  supplying  us  with  needful 
fuel  when  other  sources  fail  ? 

"  But  what  shall  we  do,"  says  a  forward  -  looker, 
"  when  the  water  of  the  earth  is  all  burned,  the  earth 
cold,  the  coal  gone,  and  the  oil  consumed  ?  "  We  shall 
never  meet  with  such  disaster ;  for  this  reason,  —  when 
hydrogen  and  oxygen  gases,  of  which  water  is  com- 
posed, are  burned,  water  is  produced  by  their  combus- 
tion in  exact  proportion  to  the  amount  of  the  gases 
used ;  so  that  it  might  be  burned  over  and  over  agaJn 


314  LECTURES  ON  GEOLOGY. 

forever.  As  long  as  the  world  exists,  then,  we  may  be 
assured  that  man's  ingenuity  will  keep  pace  witt  his 
necessities  of  this  kind,  and  the  human  race  march  on  to 
toe  goal  that  shall  lie  before  them. 

Man  is  an  important  part  of  Nature ;  and  his  inipor- 
tance  increases  hourly.  At  first  a  helpless  log,  he 
floated  on  the  stream,  but  now  stems  the  current,  01 
boldly  directs  it. 

If  the  land-surface  of  the  globe  should  not  increase 
naturally  in  the  future,  as  we  have  anticipated,  man's 
agency  would,  without  doubt,  bring  it  to  pass,  as  is  evi- 
dent from  what  he  has  already  accomplished. 

In  Lincolnshire,  England,  four  hundred  thousand  acres 
of  fever-and-ague-breeding  swamp-land  have  been  trans- 
formed into  fields  of  wheat,  barley,  and  oats,  and  excel- 
lent meadows.  In  the  Netherlands,  lands  lying  still 
lower  than  the  fens  of  Lincolnshire,  and  apparently 
much  more  hopelessly  doomed,  have  been  reclaimed, 
and  become  among  the  most  productive.  It  has  been 
calculated  that  nearly  nine  hundred  thousand  acres  have 
been  gained  there  by  diking  and  draining.  "  The  prov- 
ince of  Zealand  consists  of  islands  washed  by  the  sea 
on  their  western  coasts,  and  separated  by  the  many 
channels  through  which  the  Schelde  and  some  other 
rivers  find  their  way  to  the  ocean.  In  the  twelfth  cen- 
tury, these  islands  were  much  smaller  and  more  numerous 
than  at  present.  They  have  been  gradually  enlarged, 
and,  in  several  instances,  at  last  connected  by  the  exten- 
sion of  their  system  of  dikes.  Walcheren  is  formed  of  ten 
islets  united  into  one.  At  the  middle  of  the  fifteenth 
century,  GToeree  and  Overflakkee  consisted  of  separate 
islands,  containing  altogether  about  ten  thousand  acres. 
By  means  of  above  sixty  successive  advances  of  the 


LECTURES  ON  GEOLOGY.  315 

dikes,  they  have  been  brought  to  compose  a  single  island, 
whose  area  is  not  less  than  sixty  thousand  acres."* 

A  few  years  ago,  an  English  gentleman  purchased  for  a 
trifling  sum  a  small  island  which  was  covered  by  the  sea 
every  flood-tide,  but  left  dry  at  the  ebb.  He  enclosed  it 
with  a  bank  of  earth  thirty  feet  wide  at  the  bottom,  and 
seven  feet  high  and  four  feet  wide  at  the  top,  with  a 
slope  on  the  outside  having  two  feet  horizontal  to  one 
perpendicular.  This  wall,  about  two  miles  and  a  half 
long,  encircled  the  island,  except  a  gap  about  seventy 
feet  wide,  through  which  the  tide  flowed  in  and  out. 
Earth  was  at  first  used  to  close  the  gap ;  but  the  sea 
swept  it  away  as  fast  as  it  was  thrown  in.  Piles  were 
then  driven  in  a  double  row,  and  clay  rammed  in  between 
them.  This  succeeded,  and  the  little  island  was  drained. 
In  time,  excellent  crops  were  raised  upon  it,  a  house  and 
barn  built,  and  nearly  three  hundred  acres  of  land,  by 
the  energy  of  one  man,  won  from  the  sea. 

The  draining  of  Lake  Haarlem  is  one  of  the  best 
examples  that  we  possess  of  man's  disposition  and  power 
to  change  water-surfaces  into  dry  land ;  and  is  at  the  same 
time  a  prophecy  of  what  will  be  done  in  the  future, 
when  the  earth  shall  be  as  densely  populated  over  its 
whole  extent  as  it  is  now  in  Holland. 

Here  was  a  lake  fifteen  miles  long,  and  seven  broad 
in  its  greatest  width.  "  What  fine  farms  we  might  have 
here,"  said  an  enterprising  Hollander,  "  if  this  lake  were 
only  drained  !"  —  "Yes;  but  it  lies  below  the  sea-level, 
and  it  would  be  impossible  to  drain  it."  —  "  Then  we  must 
pump  it  dry."  —  "  Pump  it  dry  !  Who  ever  heard  of  such 
an  absurdity  ?  "  But  pump  it  dry  they  did.  For  this 
purpose,  three  large  steam-engines  were  employed,  each 

*  Man  and  Nature:  Marsh. 


316  LECTURES  ON  GEOLOGY. 

pumping  a  million  tons  of  water  in  twenty-five  and  a 
half  hours.  They  commenced  pumping  in  May,  1848; 
and  laid  it  dry  in  July,  1852.  Where  the  boats  sailed 
and  the  fishes  swam  are  now  comfortable  cottages,  fer- 
tile fields,  and  a  population  of  five  thousand  thriving  citi- 
zens. In  the  same  country,  it  is  now  proposed  to  drain 
the  Zuyder  Zee,  which  covers  two  thousand  square  miles. 
The  time  will  come  when  the  land  under  Lake  Erie  will 
be  of  more  value  than  the  water  within  it ;  and,  when  that 
time  comes,  man  will  say  to  the  waters,  "  March  ! "  and 
they  wiU  go,  leaving  the  land  for  man's  occupancy.  Its 
greatest  depth  is  but  two  hundred  and  seventy  feet,  and 
its  drainage  would  be  an  easy  matter.  In  like  manner, 
the  lands  of  Lakes  Michigan  and  Superior  will  be  needed, 
demanded,  and  obtained,  and  the  sea  be  made  to  give  up 
a  large  portion  of  its  shallow  shores  to  supply  man's 
constantly-increasing  demand  for  room. 

Many  of  these  statements  regarding  the  future  are 
evidently  based  on  the  supposition  that  the  population 
of  the  world  will  be  much  greater  in  the  future.  This 
will  doubtless  be  the  case.  When  the  age  of  shells  was, 
shells  were  so  numerous  that  their  accumulated  remains 
made  beds  thousands  of  feet  in  thickness :  universal 
ocean  swarmed  with  testaceous  inhabitants.  When  the 
age  of  plants  was,  so  numerous  were  they,  that  the 
world's  fuel  for  thousands  of  years  to  come  is  merely 
the  excess  of  that  vegetation  then  buried.  Reptiles 
and  beasts  have  in  their  turn  held  dominion  over  the 
earth,  and  their  fossil  remains  indicate  their  existence  in 
prodigious  numbers,  which  had  apparently  for  their  hab- 
itation the  universal  earth.  So,  when  the  age  of  man  shall 
have  fully  come,  he  will  fill  the  world,  and  hold  domin- 
ion over  the  entire  globe.  For  one  man,  there  will  be  at 


LECTURES  ON  GEOLOGY.  317 

least  a  hundred  men;  and  of  course,  for  one  woman,, a 
hundred  women  ;  and,  as  a  consequence,  those  who  shall 
then  live  will  enjoy  existence  much  more  than  the  soli- 
taries of  the  present. 

Every  year  finds  the  laws  of  health  better  known  and 
rrore  faithfully  obeyed.  We  have  learned  that  our  dis- 
eases are,  as  a  general  thing,  the  consequences  of  our 
misconduct ;  and  consequently,  by  avoiding  the  causes, 
we  escape  the  consequences,  and  life  is  thereby  length- 
ened. Hence,  in  nearly  all  civilized  countries,  the  aver- 
age duration  of  human  life  steadily  increases.  In  Ge- 
neva, accurate  registers  have  been  kept  for  three  hun- 
dred years.  From  1560  to  1600,  the  average  life  of  a 
citizen  was  twenty-one  years  two  months ;  in  the  rext 
century,  twenty-five  years  nine  months ;  in  the  cen- 
tury following,  thirty-two  years  nine  mouths;  and  in 
1333,  forty  years  five  months.  Thus,  in  less  than  three 
hundred  years,  the  average  duration  of  human  life  is 
nearly  doubled  among  the  constantly-increasing  intelli- 
gent population  of  this  Swiss  city.  In  the  four- 
teenth century,  the  rate  of  mortality  in  Paris  was  one 
in  sixteen :  it  is  now  one  in  thirty-two.  In  England,  the 
rate  of  mortality  in  1690  was  one  in  thirty-three;  in 
1780,  it  was  one  in  forty.  Yet,  even  now,  millions  die 
before  their  time.  Multitudes  of  children  are  murdered 
before  they  see  the  light;  others  are  born  with  enfeebled 
constitutions,  owing  to  the  ignorance  of  their  parents: 
the  same  ignorance  causes  one-half  of  them  to  die  before 
they  are  ten  years  of  age.  It  is  only  by  looking  back  a 
sufficient  distance  that  we  can  see  that  any  improvement 
has  taken  place;  but,  when  we  do  thus  look,  the  future 
is  full  of  hope.  The  population  of  the  United  States 
increases  with  ur  3xampled  rapidity :  the  million  and  a 


318  LECTURES   ON  GEOLOGY. 

half  in  New  York  and  its  suburbs  —  so  young  a  city — 
is  a  fin 3  example  of  this  increase.  The  population  of 
Canada  increases  at  the  rate  of  ten  thousand  a  year. 
In  London,  there  are  six  hundred  more  mouths  to  feed 
every  week ;  and  these  are  indications  of  the  progress 
in  population  making  in  civilized  countries  generally. 
Thus,  in  time,  will  the  whole  earth  be  peopled  by  intelli- 
gent men;  for  this  is  evidently  its  destiny,  toward  which 
it  has  been  striding  from  the  earliest  period  of  its 
history. 

But  how  shall  such  a  great  population  be  fed?  Already 
the  crowded  populations  of  Europe  are  making  their  way 
to  our  shores,  and  surging  in  wave  after  wave  over  our 
broad  lands.  There  is  no  real  necessity  for  this  emigra- 
tion from  Europe.  There  are  millions  of  acres  of  untilled 
land  in  Great  Britain,  that  the  poor  would  gladly  culti- 
vate if  they  were  allowed.  I  have  walked  in  England 
for  thirty  miles  over  one  man's  land,  most  of  it  in  a  state 
of  nature,  —  poor  land,  it  is  true,  but  capable,  by  judi- 
cious culture,  of  producing  excellent  crops. 

The  lands  that  are  cultivated  will  be  much  improved 
in  the  time  to  come.  Our  agricultural  methods  are  still 
rude,  and  must  be  considered  so  while  the  plough  is  the 
symbol  of  agriculture.  I  can  look  back  and  see  the  first 
cultivator  of  the  soil,  a  naked  savage,  who  tries  the 
first  agricultural  experiment  by  making  a  hole  with 
his  finger  in  the  mud  left  by  the  overflowing  waters 
of  some  river,  and  depositing  a  grain  of  wild  corn. 
How  he  grins,  on  his  return,  to  see  the  success  of  his 
experiment  in  the  silken  tassel,  and  eventually  in  the 
golden  ears!  He  tries  again  ;  but,  finding  his  forefinger 
sore  from  use,  he  improves  on  this  by  using  a  stick  to 
dibble  in  the  grains,  and  thus  invents  the  first  agricultural 


LECTURES  ON  GEOLOGY.  319 

todl.  His  tribe  learn  from  his  example,  and  pursue  the 
same  course.  But  land  suitable  for  their  purpose  becomes 
scarce,  and  the  hard  land  must  be  used.  A  stone  hatchet 
hews  out  the  first  rude  spade,  and  with  this  wooden 
spade  the  work  goes  bravely  on.  I  look  down  the  stream 
of  time,  and  see  the  wooden  spade  disappear,  and  a  stick 
pulled  by  an  ox  take  its  place ;  follows  the  Saxon  peas- 
ant with  his  wooden  plough,  zeeing  over  the  ground,  scat- 
tering his  grain  and  reaping  his  scanty  harvest,  but 
thinking,  proud  soul !  that  never  was  such  invention  as 
his  plough.  What  can  possibly  supersede  it?  Here 
comes  the  Yankee  farmer  with  his  steel  plough  and 
splendid  team,  turning  over  the  broad  furrow  to  the 
sun's  eye,  then  with  a  harrow  mellowing  the  rich  soil,  and 
with  a  drill  sowing  the  grain  in  parallel  rows :  he  fills  his 
barns  with  plenty,  and  exclaims,  "Where  is  the  man  that 
can  improve  upon  this?"  He  is  already  born.  I  can  see 
the  great  steam  pulverizer,  that  shall  supersede  the 
plough  as  surely  as  the  plough  superseded  the  rough- 
he  wn  spade  of  the  savage,  stirring  up  the  ground  to 
the  depth  of  two  or  three  feet,  and  making  it  all  as  fine 
as  the  finest  garden-mould.  Then  comes  the  steam-dib- 
bler,  planting  every  grain  at  an  exact  distance  from  every 
other ;  not  one  here,  and  another  there,  as  at  present,  like 
the  plums  in  a  miser's  pudding,  or  crowded  together 
like  the  dollars  in  his  bags,  but  springing  up  and  stand- 
ing like  the  chess-men  on  a  board,  with  room  enough  to 
tiller  out  on  every  side.  Weeds  destroyed,  the  land  will 
produce  the  crops,  and  nothing  else,  —  crops  that  at  this 
time  would  appear  to  us  perfectly  fabulous. 

We  shall  not  waste  as  we  do  now.  Americans  are 
doubtless  the  most  wasteful  people  in  the  world.  What 
is  wasted  in  the  United  States  alone  would  feed  half  of 


320  LECTURES  ON  GEOLOGY. 

Great  Britain.  We  shall  not  use  intoxicating  drinks: 
they  add  nothing  to  man's  bodily  vigor,  nothing  to  his 
mental  ability.  Think  of  the  corn  and  potatoes  wasted, 
worse  than  wasted,  to  make  whiskey;  grapes  turned 
into  wine  and  brandy,  sugar  into  rum ;  to  merely  men- 
tion cherries,  apples,  peaches,  transformed  by  infernal 
art  into  poisonous  liquors.  This  must  all  cease,  and  the 
food  wasted  be  redeemed  for  the  service  of  mankind. 

The  tobacco  used  in  the  United  States  in  a  year,  if 
taken  at;  one  dose,  would  destroy  every  human  being  on 
the  globe.  Hundreds  of  thousands  of  acres  of  the  best 
land  are  set  apart  for  the  culture  of  this  vile  weed,  — 
four  hundred  thousand  in  the  United  States  alone,  — 
which  doctors,  lawyers,  parsons,  and  senators  roll  in  their 
mouths,  though  as  poisonous  as  the  venom  of  the  rattle- 
snake. The  land  and  labor  employed  in  its  produc- 
tion shall  likewise  be  redeemed  ;  for,  in  the  light  of  the 
day  that  is  dawning,  such  demons  as  these  shall  vanish 
from  the  earth. 

Land  now  considered  worthless  shall  be  made  to  yield 
abundance  j  for  the  desert  must  rejoice,  and  the  wilder- 
ness blossom  as  the  rose.  Sahara  is  a  name  typical  of 
barrenness  and  desolation;  and  yet  see  what  science  has 
accomplished  even  there  !  The  French  have  bored  a 
number  of  artesian  wells  in  the  desert  near  Algiers,  and 
the  natives  are  now  doing  the  same  thing.  Beneath  the 
sand  lies  a  bed  cf  clay ;  and,  when  this  is  perforated,  up 
comes  the  water  in  a  perennial  fountain.  On  the  first 
trial,  after  a  few  weeks'  labor,  a  constant  stream  flowed 
out,  yielding  four  thousand  quarts  of  water  a  minute. 
Before  the  end  of  1860,  several  tribes  had  abandoned 
their  wandering  life,  planted  palm-trees,  and  commenced 
the  cultivation  of  the  soil.  Laurent,  a  French  writer 


LECTURES  ON  GEOLOGY.  321 

q  joted  by  Marsh,  says,  "  In  the  anticipation  of  our  suc- 
cess at  Oum-Thiour,  every  thing  had  been  prepared  to 
take  advantage  of  this  new  source  of  wealth  without  a 
moment's  delay.  A  division  of  the  tribe  of  the  Selmia, 
and  their  sheik,  laid  the  foundation  of  a  village  as  soon  as 
the  water  flowed,  and  planted  twelve  hundred  date-palms, 
renouncing  their  wandering  life  to  attach  themselves  tc 
the  soil.  In  ihis  arid  spot,  life  had  taken  the  place  of 
solitude,  and  presented  itself  with  its  smiling  images  to 
the  astonished  traveller.  Young  girls  were  drawing 
water  at  the  fountain ;  the  flocks,  the  great  dromedaries 
with  their  slow  pace,  the  horses  led  by  the  halter,  were 
moving  to  the  watering-trough  ;  the  hounds  and  the  fal- 
cons enlivened  the  group  of  party-colored  tents ;  and  liv- 
ing voices  and  animated  movement  had  succeeded  to 
silence  and  desolation." 

Between  1856  and  1860,  fifty  artesian  wells  were  bored, 
and  thirty  thousand  palm-trees  planted. 

There  is  no  land  so  poor  that  intelligence  and  indus- 
try cannot  enrich  it.  The  Chinese  carry  earth  up  the 
mountains,  and  deposit  it  on  the  bare  rock,  on  which  they 
succeed  in  raising  valuable  crops ;  and  it  is  said  that 
much  of  the  wine  of  Moselle  is  obtained  from  grapes 
grown  on  earth  carried  up  the  cliffs  on  the  shoulders  of 
men. 

The  lands  that  man's  ignorance  and  wickedness  have 
cursed  shall  be  blessed  and  redeemed  by  his  intelligence 
and  virtue.  Virginia,  doubly  cursed  by  raising  slaves 
and  tobacco,  shall  become  what  it  may  easily  be,  —  the 
orchard  of  America.  Palestine  shall  yet  be  what  it  is 
said  to  have  been,  "  a  land  flowing  with  milk  and  honey." 
The  Valleys  of  the  Tigris  and  Euphrates  shall  be  regen« 
crated  and  repeopled  by  a  greater  population  than 

21 


322  LECTURES  ON  GEOLOGY. 

Nineveh  or  Babylon  ever  knew.  With  free  govern* 
merits  that  will  guarantee  men  the  fruit  of  their  labor ; 
above  all,  with  communities,  which  must  be  eventually 
established,  laboring  for  the  general  welfare,  and  aided 
by  all  the  capital  and  intelligence  of  a  neighborhood  com- 
bined,—  the  run-down,  worn-out  old  lands  of  Asia  and 
Europe  shall  be  made  once  more  to  yield  their  increase, 
and  administer  to  man's  well-being. 

The  earth  was  all  a  desert  once  ;  and,  after  so  much  of 
it  has  been  made  fertile  without  our  agency,  it  would  be 
pitiful  if  we  could  not  finish  the  remainder.  The  time 
and  labor  and  life  spent  by  the  world  in  war  would 
have  pounded  every  bowlder  in  the  land  to  dust  to  make 
soil,  bored  a  hundred  thousand  artesian  wells,  and 
drained  every  swamp ;  it  would  have  made  —  used  in 
accordance  with  our  highest  modern  culture  —  every 
desert  a  garden,  and  every  wilderness  a  fruitful  field. 
War  is  not  to  last  forever  :  it  is  the  game  of  fools ;  and, 
when  men  are  wise,  they  will  play  it  no  more.  The 
energy,  the  wealth,  the  increased  intelligence,  of  man- 
kind, will  be  employed  to  overcome  the  physical  evils 
that  surround  us ;  and  then  the  millennium  that  man  is 
commissioned  to  make  will  have  come. 

The  question  is  sometimes  asked,  "Will  a  new  race  of 
beings  ever  inhabit  the  earth  as  much  superior  to  the 
present  as  they  are  superior  to  the  forms  that  preceded 
them  ?  Will  the  time  ever  come  when  man  will  be  super- 
seded by  some  superior  being,  and  he  be  only  known  by 
fossil  remains  as  an  extinct  form, — one  of  the  shapes 
assumed  by  life  in  its  march  though  the  ages,  and  laid 
down  when  its  purpose  was  answered,  and  a  mere  fitting 
one  assumed  ?  "  If  the  reptiles  of  the  Carboniferous 
could  have  reasoned  from  the  then  past  history  of  the 


LECTURES   ON  GEOLOGY.  323 

globe,  they  would  have  doubtless  said,  "  The  world  was 
made  for  us :  what  intelligent  reptile  can  doubt  it  ?  Life 
advanced,  during  long  ages,  from  the  radiate  to  the  mol- 
lusk  and  articulate,  from  them  to  the  fish,  and  lastly  to 
us,  its  highest  representatives.  Behold  the  perfection 
of  our  forms !  See  these  lungs  that  breathe  the  vital  air, 
which  all  others  have  obtained  from  the  water  by  clumsy 
gills;  these  limbs  that  elevate  us  above  the  ground,  and 
by  which  we  can  swim  in  the  water,  or  walk  or  run  upon 
the  land!  What  reptile  can  conceive  of  a  more  perfect- 
form  than  ours  ?  Nature  exhausted  her  resources  in  its 
production.  The  world  was  made  for  reptiles,  and  will 
be  a  reptile  world  as  long  as  it  endures." 

When  birds  made  their  appearance,  how  could  they 
doubt  that  they  were  creation's  fairest,  best,  and  last 
ordained  ?  "  What  being  can  possibly  surpass  us  ?  We 
are  at  home  in  the  water,  on  the  land,  and,  superior  to 
all,  in  the  air.  It  is  impossible  that  any  being  should 
ever  arise  superior  to  us."  May  we  not,  in.  like  manner, 
be  flattering  ourselves,  looking  only  at  the  past,  and  not 
at  the  possibilities  of  the  great  future  ? 

I  regard  man  as  the  fruit  of  the  tree  of  life ;  and,  if  he 
is,  beyond  the  fruit  the  tree  cannot  go.  A  tree  advances 
from  root  to  stem,  from  stem  to  branch,  from  branch  to 
leaf,  and  from  leaf  to  blossom  and  fruit,  each  rising  in 
importance  above  the  other;  but,  when  the  fruit  is 
attained,  all  that  can  be  done  is  to  perfect  it.  The  root 
of  the  great  tree  of  life  is  the  radiata,  their  raying,  rami- 
fying arms  and  fingers  forming  its  spreading  radicles  ; 
the  trunk  of  this  tree,  the  mollusca;  their  shelly  covering, 
its  bark.  The  jointed  bodies  of  the  articulates  form  its 
branches  the  vertebrates  are  the  leaves.  Every  leaf  has 
a  mid-rib  passing  through  its  centre,  from  which  ribs  go  to 


324  LECTURES  ON  GEOLOGY. 

each  side  of  the  leaf  to  strengthen  it,  as  in  vertebrates 
the  back-bone  passes  through  the  centre  of  the  animal, 
and  ribs  proceed  from  it  on  both  sides.  The  blossoms  are 
the  mammalia  or  milk-producing  animals  ;  and  its  fruit 
humanity,  waiting  for  the  ages  to  ripen  it.  This  ^rand  old 
Iree  has  been  advancing  for  ages,  renewing  its  rootlets, 
shedding  its  old  bark,  losing  unnumbered  branches  in 
the  storms  of  the  past,  and  dropping  myriads  of  leaves 
and  blossoms,  but,  with  a  sound  heart,  reproducing 
better  than  it  lost,  and  fruiting  in  good  time  with  the 
promise  of  the  best  when  that  fruit  is  fully  ripe.  But 
what  evidence  is  there  that  man  is  the  fruit  of  this  won- 
derful tree  V  What  peculiarity  is  there  in  the  fruit  of  a 
tree  that  distinguishes  it  from  every  other  part?  It  con- 
tains a  living  principle  which  possesses  unlimited  dura- 
tion, and,  under  favorable  circumstances,  may  unfold  into 
a  tree  equal  or  superior  to  that  from  which  it  sprang. 
Let  a  piece  of  the  root  be  separated  from  the  tree,  it 
speedily  dies,  and  is  resolved  to  dust :  in  like  manner, 
bark,  branches,  blossoms,  leaves,  perish  when  their  con- 
nection with  the  parent  plant  is  dissevered.  The  fruit 
alone  contains  the  power  of  continuous  existence  within 
itself.  Drop  it  on  the  ground,  or  bury  it,  and  it  lives  and 
grows,  and  sends  its  type  down  the  ages:  so  man.  The 
polyp,  the  snail,  the  worm,  the  fish,  reptile,  bird,  and 
beast  may  die  when  death  comes,  and  return  to  the  un- 
distinguished dust  from  which  they  sprang  ;  but  man  pos- 
sesses that  over  which  death  has  no  power,  and  the 
extinction  of  one  life  is  but  the  dawn  of  another  of 
greater  power  and  beauty.  Some  there  are  who  doubt 
this ;  to  such  this  argument  will  have  no  weight :  but  to 
those  who  believe  in  the  souPs  future,  and  to  others,  who, 
like  myself,  know  that  we  continue  to  live  hereafter,  the 
reasonableness  of  this  will  be  apparent. 


LECTURES  ON  GEOLOGY.  325 

Did  not  man  possess  the  power  of  unlimited  progress, 
he  would  be  dropped  for  some  form  superior  to  him  in 
this  respect.  Nature  progressed  in  the  fish  till  the  fish 
could  advance  no  farther  and  be  a  fish ;  she  then  progressed 
in  the  reptile,  till,  in  the  pterodactyle  and  allied  forms, 
they  could  advance  no  farther  and  be  reptiles ;  she  then 
chose  the  bird,  and  for  the  same  reason  left  it  behind,  and 
took  up  the  beast;  she  has  now  chosen  man  in  whom 
To  embody  this  principle,  and  in  him  she  finds  that  power 
of  unlimited  progress  which  satisfies  her.  We  stand  on  the 
platform  that  our  progenitors  built,  and  we  build  higher 
for  our  children :  in  their  turn,  they  elevate  it  for  the  next 
generation.  As  a  race,  then,  we  satisfy  the  law,  and  as 
individuals.  The  great  future  opens  its  portals  for  us, 
and  presents  us  a  boundless  field  for  our  advancement. 

As  the  earth  is  being  gradually  cured  of  its  evils,  and 
as  its  organic  forms  have  been  manifested  in  continually 
progressive  forms,  so  we  may  reasonably  expect  a  supe- 
rior race  of  human  beings,  and  the  eventual  destruction, 
by  the  growth  of  the  superior  faculties,  of  the  moral  evils 
that  war  with  our  highest  interests.  As  we  have  out- 
grown cannibalism,  to  which  our  forefathers  were  addict- 
ed ;  as  we  have  advanced  from  the  wild  savages  with 
rude  stone  weapons  that  hunted  the  mammoth  through 
the  woods  of  Great  Britain,  and  dwelt  in  caves  by  the 
shore :  so  shall  we  outgrow  war,  intemperance,  licen- 
tiousness, lying,  bigotry,  and  every  form  of  wrong-doing, 
and  grow  into  intelligence,  culture,  and  every  manly 
virtue,  —  lovers  and  loved  of  all. 

What  will  be  the  final  destiny  of  the  earth  ?  As  there 
was  a  time  when  the  world  was  not,  so  there  will-come 
a  time  when  it  will  cease  to  exist.  When  fruit-trees  can 
produce  fruit  no  longer,  they  die,  and  return  to  the  earth, 


326  LECTURES  ON  GEOLOGY. 

to  give  place  to  those  that  can  produce  fruit  in  turn;  and 
when  the  earth  is  old,  worn  out,  and  can  no  longer  admin- 
ister to  man,  then  we  may  reasonably  expect  that  it  will 
die,  and  return  to  the  sun,  from  which  it  probably  came. 
It  has  been  a  common  opinion  that  the  heavenly  bodies 
revolve  in  a  vacuum :  but  scientific  men  now  generally  be- 
lieve that  space  is  occupied  by  some  resisting  medium  ; 
and,  however  finely  attenuated  it  may  be,  its  influence 
upon  the  planets  moving  in  it  must  be  such  as  to  retard 
their  motion,  and  eventually  bring  them  to  the  sun. 
Littrow,  as  quoted  by  Mayer,  says,  "  The  assumption 
that  the  planets  and  comets  move  in  an  absolute  vacuum 
can  in  no  way  be  admitted.  Even  if  the  space  between 
celestial  bodies  contained  no  other  matter  than  that 
necessary  for  the  existence  of  light  (whether  light  be 
considered  as  emission  of  matter  or  the  undulation  of 
a  universal  ether),  this  alone  is  sufficient  to  alter  the 
motion  of  the  planets  in  the  course  of  time,  and  the 
arrangement  of  the  whole  system  itself.  The  fall  of  all 
the  planets  and  the  comets  into  the  sun,  and  the  destruc- 
tion of  the  present  state  of  the  solar  system,  must  be  the 
final  result  of  this  action." 

The  smaller  any  cosmical  body  is,  the  faster  it  will 
move  toward  the  sun  :  hence,  although  we  cannot  ob- 
serve this  tendency  in  the  large  planets,  on  account  of 
their  size,  in  some  of  the  cornets  it  is  plainly  visible. 
Encke  found  that  the  "comet  named  after  him,  which 
revolves  around  the  sun  in  1,207  days,  has  its  motion 
so  accelerated  as  it  approaches  the  sun,  that  the  time  of 
such  revolution  is  shortened  by  about  six  hours.  The 
comets  are  grand  celestial  moths  flying  round  and  round 
the  central  luminary,  and  eventually  destined  to  plunge 
into  it  and  end  their  dazzling  career.  In  their  fate  we  may 


LECTURES  ON  GEOLOGY.  327 

see  our  own.  One  by  one,  the  planets  shall  be  gathered 
home.  Mercury  and  Venus  shall  march  to  their  graves 
before  us,  and  perhaps  enable  us  to  calculate  the  time 
of  our  endurance.  The  sun  itself  may  eventually  return 
to  the  grand  central  sun  around  which  it  revolves,  and 
the  matter  composing  it  be  again  sent  out  in  suns  and 
planets  in  the  great  eternity  of  the  future,  as  may  have 
been  the  case  in  the  equally  great  eternity  of  the  past. 


GLOSSARY 


OF 


SCIENTIFIC  AND  DIFFICULT  TEEMS  USED  IN  THIS  VOLUME. 


Those  defined  in  the  Text  may  be  found  in  the  Index. 


ADAMANTINE,  like  adamant;  which  is  a  name  given  to  the  diamond  and  other 

bodies  of  great  hardness. 
AGGLOMERATED,  collected  into  a  ball. 

AMPHIBIAN,  an  animal  so  constituted  as  to  be  able  to  live  in  water  and  on  land. 
AMYGDALOIDAL  TRAP  (amygdala,  an  almond),  one  of  the  forms  of  trap-rock  in 

which  enclosed  minerals  are  embedded  in  roundish  bodies. 
ANTHRACITE,  a  bright,  hard  coal  that  burns  without  smoks  or  flame,  the  bitumen 

having  been  driven  off  by  heat. 
ARCHEOPTERYX  (arche,  beginning;  pteryas,  a  wing),  a  reptilian  bird  of  Solen- 

hofen. 

ARID  (aridus,  dry),  parched  with  heat,  destitute  of  moisture. 
ARMADILLO,  an  insectivorous  mammal  of  South  America,  covered  with  a  hard, 

bony  shell  composed  of  movable  bands. 
ARMATURE,  armor;  that  which  defends  the  body. 

BITUMINOUS,  containing  bitumen,  an  inflammable  substance,  found  of  varying 

consistence,  from  naphtha  to  asphaltum. 
BOWLDER,  a  rounded  mass  of  rock,  generally  found  at  a  distance  from  its  original 

position. 

BRECCIA,  a  rock  made  up  of  angular  fragments  cemented  together. 
BRYOZOAN  (bryon,  moss,  and  zoon,  an  animal),  small  mollusks  which  grow 

together  on  a  common  stock,  and  so  much  resemble  polyps  that  they  were 

formerly  arranged  with  them. 

BUCKLER,  the  shield  or  body-covering  of  an  animal. 
BURIN,  a  sharp-pointed  instrument  used  by  engravers  for  marking. 

CANADA  BALSAM,  a  kind  of  turpentine  obtained  from  the  balm-of-Gilead  fir. 
CANNEL-COAL,  originally  candle-coal,  and  so  called  because  it  is  an  inflammable 
coal  that  will  burn  like  a  caudle. 


330  GLOSSARY. 

CANNELITE,  a  highly  bituminous  shale,  generally  found  in  the  neighborhood  of 

petroleum  coal. 

CANYON,  a  chasm  cut  by  a  river  with  walls  nearly  or  quite  perpendicular. 
CARBONIC- ACID  GAS  (carbo,  coal),  a  heavy,  poisonous  gas  composed  of  one  part 

of  carbon  and  two  parts  of  oxygen.    It  frequently  issues  from  the  ground  in 

volcanic  countries,  and  is  often  found  in  wells  and  mines. 
CARBURETTED-HYDROGEJI  GAS,  an  inflammable  gas  composed  of  carbon  and 

hydrogen,  which  is  very  abundant  in  coal-mines. 
CARICATURE,  an  exaggerated  figure,  bearing  only  a  distant  resemblance  to  the 

object. 

CARPUS,  that  part  of  the  skeleton  which  forms  the  wrist. 
CHALCEDONY,  a  translucent  variety  of  quartz. 
CHEIROMANCER,  one  who  tells  fortunes  by  the  hand. 
CHERT,  an  impure  variety  of  flint. 
CHIMPANZEE,  an  ape  found  on  the  western  coast  of  Africa,  which,  next  to  the 

gorilla,  most  resembles  man. 
CLIMATAL,  relating  to  climate. 

CLUB-MOSS,  a  moss-like  plant  intermediate  between  a  fern  and  a  moss. 
CONCENTRIC,  having  a  common  centre. 
CONCHOIDAL  (concha,  a  shell),  having  curved  elevations  and  depressions  in  form, 

like  the  valve  of  a  shell. 

CONGLOMERATE,  rock  made  of  pebbles  cemented  together;  sometimes  called  pud- 
ding-stone. 

CONICAL,  in  the  shape  of  a  cone  or  sugar-loaf. 
CONIFER,  a  plaut  bearing  cones.    The  pines  aud  firs  are  conifers. 
CONIFEROUS,  bearing  cones* 
COPROLITE,  fossil  dung. 
CRANIUM,  the  skull  of  an  animal. 
CRATER  (crater,  a  cup),  the  circular  cavity  of  a  volcano,  from  which  the  matter 

of  an  eruption  is  ejected. 
CRESSET,  a  great  light  set  on  a  watch-tower. 
CRUSTACEAN,  an  articulate  animal  covered  with  a  crust  or  shell,  like  a  crab  or 

lobster. 
CYCAD,  a  plant  growing  in  warm  countries,  which  is  intermediate  in  its  structure 

between  pines  and  palms. 
CYSTIDEAN,  a  radiate  animal  belonging  to  the  family  of  crinoids.    They  are  only 

found  in  a  fossil  state. 

DEBRIS  (pronounced  da-bree'),  fragments  detached  from  rocks,  and  piled  up  in 


DETRITUS,  sand,  fine  gravel,  or  clay,  worn  from  solid  bodies  by  water  or  ice. 
DIGIT  (digitus,  a  finger),  a  finger. 

DILUVIUM,  in  this  volume  it  means  the  time  when  the  glacial  beds  were  deposited. 
DISINTEGRATING,  wearing  down  to  fine  particles. 

ECHINITE,  a  fossil  echinus. 

ECHINODERM  (echinus,  hedge-hog;  derma,  skin),  a  radiate  animal,  generally  of 

a  nearly  globular  form,  and  co  Tered  with  spines.    The  sea-egg  is  a  familiar 

example. 

ECHINUS,  same  as  echinoderm. 
EDIBLE,  eatable. 


GLOSSARY.  331 

ELEMENTS,  those  bodies  which  cannot  be  decomposed  by  the  chemist,  and  of 
which  all  other  bodies  are  composed. 

ENAMEL,  the  hardest  portion  of  a  tooth;  the  smooth,  hard  substance  which  cov- 
ers or  composes  the  most  elevated  parts  of  the  tooth. 

ENTOMOLOGICAL,  relating  to  the  science  of  insects. 

EPHEMERA  (ephemeras,  daily),  a  fly  that  lives  but  for  a  short  time  ;  strictly,  a  fly 
that  lives  but  for  a  day. 

ESTUARY,  the  place  where  a  river  pours  into  the  sea  or  a  lake. 

FAHRENHEIT  THERMOMETER,  a  thermometer  invented  by  Fahrenheit,  in  which 
the  freezing-point  of  water  is  marked  32*,  and  the  boiling-point  212°. 

FATHOM,  six  feet. 

FILIGREE- WORK,  an  ornamentation  on  gold  and  silver,  worked  in  the  manner  of 
little  threads  or  grains. 

FLUOR-SPAR,  a  mineral  composed  of  the  two  elements,  fluorine  and  calcium.  Ita 
crystals  are  of  beautiful  colors. 

FRITH,  a  narrow  passage  of  the  sea,  or  an  opening  of  a  river  into  the  sea. 

FUCOID,  sea-weed. 

FUCOIDAL,  of  a  fucoid. 

GORILLA,  of  apes  the  most  man-like.    It  is  found  on  the  western  coast  of  Africa. 
GREENSTONE,  a  variety  of  trap  of  a  green  color,  containing  hornblende  and  fel- 
spar in  small  crystals. 
GUACHOS,  the  men  who  live  on  the  South- American  pampas. 

HOMOGENEOUS,  of  the  same  kind  or  nature  throughout. 

HOMOPTERA,  an  order  of  insects  having  four  membranous  wings.    They  feed  on 

the  juices  of  plants. 

HORSE-TAIL,  a  plant  that  grows  in  boggy  places,  and  allied  to  the  ferns. 
HUMERUS  (humerus,  shoulder),  the  bone  of  the  arm  nearest  the  shoulder. 
HYDRAULIC  CEMENT,  a  cement  composed  of  lime  and  clay  that  sets  under  water. 
HYDRO-CHLORIC  ACID  (sometimes  called  muriatic  acid),  a  very  powerful  acid 

composed  of  hydrogen  and  chlorine. 

ICHNOLOGICAL,  relating  to  the  science  of  fossil  footprints. 

IGNEOUS,  fiery. 

INDIGENOUS,  originally  belonging  to  a  country. 

INFILTRATION,  the  act  of  entering  the  pores  of  bodies. 

INFUSORIA,  animals  invisible  to  the  naked  eye,  and  often  found  In  vegetable  infu- 
sions. 

INTEGUMENT,  that  which  naturally  surrounds  a  thing. 

INVERTEBRATE,  destitute  of  a  back-bone.  Radiates,  shells,  and  insects  are  inverr 
tebrates. 

KING-CRAB,  an  articulate  animal  living  on  the  coast  of  New  England;  sometimes 
called  horse-foot.  Its  scientific  name  is  limulus. 

LAGOON,  a  shallow  pond  or  lake  into  which  the  sea  flows. 
LARVAE,  insect?  in  the  caterpillar  or  grub  state. 
LAVA,  the  melted  matter  that  flows  from  a  volcano. 
LENTICULAR,  havj  ig  the  form  of  a  lens. 


332  GLOSSARY. 

LIGNITE,  wood  partially  converted  into  coal. 

LIVERWORTS,  an  order  of  plants  having  short,  leafy  stems,  and  allied  to  th« 

mosses. 

MAGNESIAN  LIMESTONE,  limestone  containing  magnesia. 
MARINE,  belonging  to  the  sea-. 

MATRIX,  a  mould ;  the  cavity  in  which  a  thing  is  held. 
METACARPUS,  the  part  of  the  hand  between  the  wrist  and  fingers. 
Moss- AGATE,  a  chalcedony  containing  crystallized  manganese,  which  has  a  plant- 
like  appearance. 

NEBULAE,  cloudy  spots  in  the  heavens,  some  of  which  are  assemblages  of  stars, 

and  others  gaseous  matter  uncondensed. 
NEBULOUS,  having  the  character  of  nebulae. 
NECROMANCER,  one  who  tells  fortunes  by  departed  spirits. 
NON-NITROGENOUS,  containing  no  nitrogen. 

OCCIPITAL  BONE,  the  bone  at  the  back  part  of  the  head. 

ORGANIC,  that  which  possesses  organs  by  which  it  grows  to  perfection,  as  planti 

and  animals. 
ORNITHORYNCHUS,  a  singular  mammal  of  New  Holland,  which  possesses  a  bill 

and  webbed  feet  like  a  duck. 

PAMPAS,  the  plains  of  South  America  which  are  destitute  of  trees. 

PENTAGON,  a  figure  hav  ing  five  corners. 

PERCOLATED,  passed  through  the  interstices  or  small  holes  of. 

PHALANGES,  the  small  bones  of  the  fingers  and  toes. 

PLACO-GANOID,  partaking  of  the  nature  of  the  placoidal  and  ganoidal  fishes. 

PLASTIC,  capable  of  being  moulded. 

POLYPS,  radiate  animals  surrounded  by  arms  or  tentacles,  which  live  in  commu- 
nities, and  form  coral  by,  the  secretion  of  limy  matter. 

POST-PLIOCENE,  the  period  indicated  by  beds,  all  of  whose  fossils  are  identical 
with  living  species. 

PRAWN,  a  small  crustaceous  animal  of  the  shrimp  family. 

PRIMORDIAL  ZONE  refers  to  that  class  of  rocks  which  are  supposed  to  contain  the 
earliest  forms  of  Jife;  generally  applied  to  certain  beds  of  Bohemia. 

RADIUS,  distance  from  the  centre. 

SALAMANDER,  a  frog-like  reptile,  whose  organization  seems  to  be  between  the 

frog  and  the  lizard. 
SALIFEROUS,  salt- bearing. 
SALINE,  salty. 

SCAPULA,  the  shoulder-blade. 
SELENITE,  crystallized  sulphate  of  lime. 
SERRATED,  resembling  a  saw. 
SHALES,  tine-grained  rocks,  generally  softer  than  slates,  but  in  other  respects  re« 

sembling  them. 
SHEIK,  an  Arab  chief. 
SIDEREAL,  belonging  to  the  stars. 
SIMOIFIED,  petrified  by  silica  or  flinty  matter. 


GLOSSARY.  333 

SIMOOM,  a  hot,  dry  wind  that  blows  occasionally  in  Africa  and  South-western  Asia. 

SPECTRUM  ANALYSIS,  a  method  of  telling  the  character  of  light  by  passing  it 
through  a  glass  prism,  and  observing  the  dark  lines  that  cross  the  spectrum. 

SPHERICAL,  having  the  shape  of  a  sphere  or  ball. 

STEPPES,  the  Russian  name  for  the  large  plains  of  Northern  Asia. 

STIOMARIA  (stigma,  a  mark  or  impression),  a  genus  of  plants  found  in  the  coal- 
measures.  No  plants  at  the  present  day  resemble  them.  They  derive  their 
name  from  the  marks  left  on  the  trunk  by  the  leaves  when  they  dropped. 

ST.SATUM  (plural,  strata),  a  bed  or  layer. 

SUBMERGENCE,  the  state  of  being  under  water. 

SUTURE,  the  seam  which  unites  the  bones  of  the  skull  or  parts  of  a  shell. 

TABULATED,  having  a  flat  surface. 

TABULAE,  plates  having  a  flat  surface. 

TALCOSE-SCHIST,  a  slaty  rock  containing1  talc. 

TARANTULA,  a  stinging-spider. 

TENTACLES,  thread-like  processes,  generally  surrounding  the  mouths  of  animals, 
by  which  they  feel,  and  convey  particles  of  food  to  the  mouth. 

TEREBRATULA  (terebro,  to  bore),  a  family  of  mollusks  in  which  one  of  the  valves 
has  a  hole  for  a  ligament,  by  which  the  animal  attaches  itself  to  bodies. 

TESTACEOUS,  possessing  a  shell,  as  a  mussel  or  oyster. 

THRIPS,  an  order  of  insects  having  long  membranous  wings.  They  commit 
great  depredations  on  plants. 

TRANSITIONAL  FORM,  an  organic  form  intermediate  between  two  distinct  kinds. 

TRAP,  ancient  lava.  A  heavy  rock  of  a  greenish  color.  The  word  is  derived  from 
trappa,  a  Swedish  word  for  "  stair,"  because  rocks  of  this  kind  are  frequently 
found  in  masses,  one  above  another,  like  the  steps  of  a  stair. 

TRAP-DIKE,  a  crevice  filled  with  trap. 

TREE-FERN,  a  genus  of  ferns  very  common  in  the  coal-measures,  and  which  are 
now  found  in  Australia. 

TREMOR,  a  trembling. 

TRIGONIA  (treis,  three;  goniat  angle),  a  tribe  of  mollusks  possessing  shells  hav- 
ing three  corners. 

ULNA,  the  larger  of  the  two  bones  of  the  fore-aru? 
URUS,  the  wild  bull. 

VACUUM,  empty  space. 
VERTICAL,  directly  overhead. 

ZOOPHYTE  (zoon,  animal;  phytus,  plant),  a  term  applied  to  radiate  animals  that 
resemble  plants. 


INDEX. 


Acrodus,  203. 

Actinocrinus  proboscidialis,  128. 
Action  of  the  sea  at  Cape  May,  275. 
«        "       "    on  coast  of  Dur- 
ham, 276. 
«        "       "    on  coast  of  Kent, 

278. 

"        "        "    on   coast   of  Suf- 
folk, 277. 

u        "        "    on  coast  of  York- 
shire, 277. 
«        "        "    on  shore  of  Bay  of 

Fundy,  276. 

"        "        "    in  Holland,  278. 
"        "        "    on  islands  in  Bos- 
ton Harbor,  275. 
«        "       "    on  Isle  of  Sheppy, 

278. 

"        "       "    in  Northern  Scot- 
land, 276. 

"        "       "    on   Sullivan's    Is- 
land, 275. 

<35schna  eximia,  219. 
JEtna,  31. 
Agassiz,  on  position  of  vertebrates, 

81. 

Age,  of  the  earth,  65-71. 
"    offish,  110-125. 
"    of  mammals,  206-242. 
"    of  man,  316. 
"    of  mir.srals,  55-64. 


Age,  of  plants,  126-147. 

"    of  radiates,  81-84. 

"    of  reptiles,  151-206. 
Ages,  of  the  world,  172,  173. 
Agriculture,  in  the  future,  319. 
Agricultural  experiment,  first,  318. 
Aleutian  Isles,  26. 
Alluvial  period,  272-288. 
Alumina,  56. 
Aluminum,  56. 
Ammonite,,  183-186. 
Amazon,  sediment  swept  down  by. 

280. 

Amber,  224. 

Andrias  Scheuchzeri,  225. 
Ananchytes  ovata,  199. 
Ancyloceras,  200. 

"  gigas,  201. 

Ansted,   Professor,    on    structure  of 

animals,  212,  213. 
Antisana,  25. 
Apteryx,  240,  242. 
Archegosaurus,  144. 
Archeopteryx,  187. 
Archeotherium,  218. 
Archimedes  Wortheni,  129. 
"  limestone,  129. 

Artesian  well,  at  Louisville,  20. 
"    at  Salzworth,  20. 
"      wells,  20. 

«    on  Sahara,  320,  321. 


836 


INDEX. 


Artesian  wells,  for  supply  of  heat, 

311,  312. 
Articulata,  78. 
Articulates,  78. 
Asterolepis,  114. 
Austen  Godwin,  on    Kent's   Hole, 

262. 
Australia,  fossil  mammals  of,  239. 


Baculite  bed,  230. 

Baculite,  200,  201. 

Baden,  warm  springs  of,  24. 

Bad  lands,  of  Nebraska,  217. 

Basilosaurus,  216. 

Bay  of  Santorin,  new  island  in,  38. 

"    of  Fundy,  17. 
Beaver,  fossil,  256. 
Belemnite,  183. 
Big  Phillips  Well,  118, 
Bimana,  207. 

Birds,  of  cretaceous  period,  205. 
Blackmore,  Sir  Eichard,  on  saltness 

of  sea,  156. 
Boiling-springs,  of  Colorado  Desert, 

204. 

Black-river  limestone,  94. 
Bone  cave,  of  Brazil,  270. 
Bos  primigenius,  261. 
Bowlders,  large,  243,  244. 
Brachiopoda,  78. 
Brakenbury's  dream,  283. 
Brixham,  cave  at,  263. 
Brandon,  eocene  beds  of,  216. 
Buckland,  Dr.,  on  nebular  theory, 

50. 
"  "      on      deinotherium, 

226. 

"  "      on  Bohemian  coal- 

mines, 135. 
"  "      on  Kirkdale  Cave, 

262. 
B later  sandstein,  167. 


Calciferous  sandstone,  88. 

Calcium,  57. 

Calymene  Blumenbachii,  94. 

Cambrian,  period,  81-83. 
"          formation,  81-84. 

Canada,  ignorant  farmer  of,  13. 

Canyons,  275. 

Carbon,  58. 

Carbonic  acid,  58. 

Carboniferous,  forest,  136,  137. 
"  period,  126-147. 

Carnivora,  207. 

Cardona,  152. 

Cassowary,  242. 

Castoroides  Ohioensis,  256. 

Catania,  32. 

Cavernal  limestone,  127-131. 

Cave,  of  Gaylenreuth,  256. 
"     at  Brixham,  263. 

Cave  tiger,  256. 

Central  heat,  21. 

Cephalaspis,  113. 

Cephalopoda,  78. 

Cephalopods,  90,  91. 

Cestracion,  188. 

Cetacea,  208. 

Chalk,  age  of,  69. 
"       formation,  extent  of,  196. 

Chlorine,  58. 

Chlorite,  59. 

Chazy  limestone,  89. 

Cheirotherium,  165. 

Chemung  group,  123. 

Cheiroptera,  207. 

Cheshire,  salt  deposit,  152. 

Climate,  improvement  of,  302,  303. 

Clinton  group,  104. 

Coal-measures,  70,  133. 

Coal,  how  formed,  134-139. 
"       of  Great  Britain,  146 
"      of  United  States,  146. 
"      mining  in  United  States,  144 
"         "       in  Europe,  145 


INDEX. 


337 


Coal,  mine  at  Sunderland,  19. 
"     mines,  English,  19. 
"     anthracite,  17. 
"     tertiary  of  Colorado,  231. 
"     for  the  future,  309,  3*0. 
roan,  Mr.,  on  eruptions  of  Mauna 

Loa,  35,  36. 
Coccosieus,  113. 

Cochrane's  Cave,  bone  breccia  of,  270. 
Colorado,  tertiary  beds  of,  219-222, 

229-232.       ' 

"         cretaceous  beds  of,  198. 
Comets,  nearing  the  sun,  327. 
Conchifera,  78. 

Coniferous  trees,  in  amber,  224. 
Conglomerate,  sub-carboniferous,  132. 
Connecticut  Valley,  159-163. 
Cooling,  of  the  earth,  53,  54. 
Copper  slate,  of  Mansfield,  149. 
Cordier,  M.,   on   contraction   of  the 

earth,  43. 

CorniferDus  limestone,  111. 
Corals,  in  Black-river  limestone,  94. 
Cotopasi,  25. 

Cracow,  salt-mines  of,  152,  153. 
Cretacec  is  period,  193-206. 

formation,  in    America, 

197-199. 

"  "  in   New   Jer- 

sey,     197, 
204,  205. 
in      Western 
Texas,  197 
-199. 
"  "  in    Colorado, 

198,  199. 

"  "  of         Rocky 

Mountains, 
205. 

"  "  trees  of,  198. 

"  "  fish  of,  203. 

"  "  reptiles       of, 

205. 


Crevice,  filled  with  lava,  16. 
Crinoids,  89,90,  127-129. 
Crioceras,  200,  201 . 
Crustaceans,  tracks  of,  87. 
Crust  of  the  earth,  thickness  of,  21. 
Ctenoid,  110. 
Cuttle-fish,  182,  183. 
Cuvier,  on  pterodactyle,  179,  180. 
"      on  fossils  of  Paris  basin,  21 1- 

214. 

Cycads,  182. 
Cycloid,  110. 

Dalmania  limulurus,  105. 

Dana,  Professor  James  D.,  on  uni- 
versal fusion  of  the  earth,  21. 

Darwin,  Dr.,  on  Cracow  salt-mines, 
153. 

Dawson,  Professor,  discoverer  of  rep- 
tiles in  coal-measures,  143,  144. 

Dead  Sea,  salt  in,  154. 

Deinotherium,  226. 

Deluge,  not  universal,  244. 

Dinornis,  241. 

Deucalion,  246. 

Devonian  period,  110-125. 
beds,  70. 

Dikelocephalus  Minnesotensis,  86. 

Dike,  of  trap,  17. 

Diprotodon  Australis,  240. 

D'Orbigny,   on  French    cretaceous 
beds,  202. 

Drift  period,  cause  of,  253,  255. 
"     deposits,  244. 
"     of  Europe,  251. 
"     of  South  America,  252. 
"     great  age  of,  67,  68. 
"     striffi,  247. 

Droitwich,  salt-spring  at,  152. 

Dura  Den,  fossil  fish  of,  112. 

Earth,  destiny  of,  325-327. 
"      peculiar  shape  of,  22. 


338 


INDEX. 


Earthquake,  of  Guadaloupe,  40. 

at  Lisbon,  40,  41. 
Earthquakes,  39-43. 

at  New  Madrid,  39. 
"  at  Cutch,  287. 

•'  in  Jamaica,  39. 

"  cause  of,  41-  44. 

"  destructive    of    human 

life,  297. 
"  will  cease,  297, 299, 304, 

305. 

Echinites,  199. 
Edentata,  208. 

Eighteen-mile  Creek,  fossils  of,  122. 
Electric  currents,  modifying  metallic 

deposits,  102. 
Elements,  56. 
Elgin,   reptile  found  in  quarry  at, 

123. 

Emu,  242. 

Encrinal  limestone,  127-131. 
English  coal-mines,  19. 
Eocene,  206-216. 

"       belt  along  the  Atlantic  coast, 

215. 
"       beds  of  Brandon,  216. 

"    of  Claiborne,  Ala.,  215. 
"         "    of  Clarke  Co.,  215. 
Epiornis,  241. 
Eruption,  of  JEtna,  32. 
"        of  Kilauea,  35. 
"        of  Mauna  Loa,  35. 
"        of  Skapta  Jokul,  33. 
"         of  Tomboro,  33. 
"         ^f  Vesuvius,  30. 
Eurypterus,  107. 
Extinct  volcanoes,  36, 37. 

Falls,  of  Ohio,  112. 

Farmer,  study  of  geology  important 

to  the,  11. 

"       ignorant,  in  Canada,  13. 
Feejee  Island,  hot  spring  on,  24. 


Felspar,  composition  of,  59. 

"        an  ingredient  of  granite,  60. 
Ferns,  found  in  coal-measures,  140. 
Fire,  its  action,  16. 
Fire-made  jocks,  17. 
First  fishes,  80,  81, 109. 
Fish,  first  appearance  of,  80,  81, 10? 
"      in  coal-measures,  142,  143. 
"      of  cretaceous  period,  203. 
"      fossil  of  Germany,  150. 
"         "     of  Sunderland,  165. 
"         "     of  Italy,  224. 
"      of  miocene,  224. 
"      of  Permian,  150. 
"      of  trias,  167. 
Flint,  how  formed,  195,  196. 
"     weapons    of   Somme    Valley, 

265. 
Floods,  all  partial,  245. 

"       various,  246. 
Food,  in  the  future,  318-322. 
Footprints,  in   Connecticut  Valley, 

159-162. 
"         on  red  shales,  Pottsville, 

133. 

Forest,  carboniferous,  136,  137. 
Fossil,  iron  ore,  104. 
"      guineas,  283. 
"      silver  pennies,  283. 
"      horse,  228. 
Fossils,  what  they  are,  72. 
"       how  formed,  73. 
"       now  forming,  282. 
"       their  use,  74,  75. 
"       in  drift,  255-270. 
"       in  Trenton  limestone,  93.* 
Fruits,  fossil,  in  London  clay,  210. 
"  "      in  Brandon  beds,  216. 

Fucoids,  87. 

"         in  Medina  sandstone,  103. 
Fuel,  for  coming  time,  308,  309-31& 
Fusus  antiquus,  233. 
Future,  disposition  to  look  into,  289. 


INDEX. 


339 


Future,  possibility  of  foretelling,  290 
"       past  the  guide  to,  290. 

Galena  limestone,  89. 
Galecynus  (Eningensis,  223,  224. 
Ganges  and  Brahmapootra,  delta  of, 

281. 

Ganoid,  109. 
Gaps,  in  formations,  reasons  of,  171, 

172. 

Gash  veins,  99. 
Gaudry,  M.,  on  flint  implements  of 

Somme  Valley,  265,  266. 
Genesee,  Palls  of,  275. 
Geysers,  of  Iceland,  23. 

"        of  Sonoma  County,  Gal.,  24. 
Glacial,  sheet  in  America,  250. 

"        period,  243-272. 
Glaciers,  of  the  Alps,  248. 

"         of  Patagonia,  252. 
GlyptodOn,  238. 

clavipes,  238. 
Goniatite,  142. 
Graham's  Island,  37. 
Granite,  59,  60. 

"        not  always  oldest  rock,  169. 
Graptolites,  95,  96. 
Graptolithus  octobrachiatus,  95. 
Great  Irish  elk,  259,  260. 
Grenelle,  artesian  well  of,  20. 
Greenhorn  River,  203. 
Greensand  group,  197. 
Guariaxato  silver-mine,  19. 
Gypsum,  57,  157,  158. 

"         formation  of,  158. 

"         uses  of,  158. 

"         in  Paris  basin,  211. 

Hall,  iTofessor,  on  change  of  organic 

forms,  108. 

"  on  coi-als  of  cornif- 
erous  limestone, 
112. 


Hamilton  group,  114,  115. 
Happiness,  by  study  of  geology,  14. 
Haarlem  Lake,  draining  of,  315,  316, 
Heads,  of  early  men,  268. 
Helderherg  group,  107. 
Herschel,  Sir  John,   on   the  eartb/a 

central  heat,  21. 
Herculaneum,  26,  28. 
Herodotus,  on  hot-springs  of  Greece, 

25. 

Heterocercal  fish,  150. 
History,  of  earth  recorded,  10. 
Hitchcock,  Professor,  on  footprints  in 

Connecticut  Valley,  160. 
Holyoke,  Mount,  155. 
Holoptychius  noblissimus,  114. 
Hornblende,  59. 
Horse,  fossil,  in  America,  228. 

"         "      of  England,  234. 
Hot-springs,  23. 

of  Colorado,  23. 
"  of  Feejee  Island,  24. 

"  of  Greece,  24,  25. 

Hudson-river  group,  95,  102,  103. 
Humboldt,  on  internal  heat,  19. 

"         on  nebular  theory,  50. 
Huxley  on  Neanderthal  skull,  269. 
Hydrogen,  58. 
Hyleosaurus,  192. 

Ice,  action  of,  during  drift  period, 
247-251. 

Ichthyosaurus,  173,  175. 

[dalio,  hot-springs  of,  23. 

Iguanodon,  189,  190. 

Infiltration,  99. 

[njection,  veins  filled  by,  100. 

Insect  shales,  219-221. 
nsectivora,  207. 

Insects,  of  lias,  182. 

"        fossil  of  Colorado,  219,  220 
"        in  Devonian  rocks,  125. 
"        in  coal-measures,  142. 


340 


INDEX. 


Insects,  in  amber,  224. 

"       noxious,    disappearance    of, 

306,  307. 
Iron,  57. 

Iron  ore,  in  Clinton  group,  104. 
Isis,  temple  of,  at  Pompeii,  29. 

Jakutsk,  18. 

Jamaica,  earthquake  in,  39. 

Kanawha  Valley,  coal  in,  133. 

Kaolin,  60. 

Kazwini,  Mohammed,  on  changes  on 

the  earth's  surface,  273. 
Kilauea,  eruption  of,  35. 
Kinahan,  Dr.,  on  Oldhamia,  82. 
Kirkdale  Cave,  26. 
Kupfer-schiefer,  149. 

Laborer,  in  the  quarry,  14. 
Laborde,  Count,  on  salt  at  Cardona, 

152. 

Labyrinthodon,  166. 
Labyrinthodont,  144. 
Land,  gaining  on  the  sea,  279-282. 

"      increase  of,  in  Zealand,  314. 

"          "         of,  in  Holland,  315, 
316. 

"          "         of,  in  England,  315. 
Laurentian  period,  81,  83. 
"  formation,  71. 

rocks,  83. 

Lava,  cooling  of,  53,  54. 
Lea,  Isaac,   discovery  of  footprints 

by,  132. 

Lead,  sulphuret  of,  101. 
Lead-region,  of  the  North-west,  101. 
Lenticular  iron  ore,  104. 
Lexington,  trap-dikes  in,  17. 
Li  as,  172-1 86. 
Li  *e,  where  it  began,  75. 

'    duration  of,  317. 
Limestone,  59. 


Limulus,  150. 
Lingula  prima,  86. 
Lithographic  stone,  187. 
Lockport,  106. 

locks  of,  105. 
London,  basin,  211-214. 
"        clay,  209,  210. 
"  "    fossil  fruits  in,  210. 

Louisville,  artesian  well  at,  20. 
Lower  Cambrian,  82. 
Lubbock,  Mr.,  on  stone  men  of  the 

Somme  Valley,  266. 
Lyell,  on  flint  weapons  of  the  Somme 

Valley,  265. 

"    on   position  of  earliest  verte- 
brates, 80. 

"     on  fossil  footprints,  163. 
"    on  discovered  reptiles,  143. 
"     on  lava  current  from  ^Etna,  32. 
"     on  nummulitic  formation,  214. 

Machairodus,  256. 
Macropoma,  203. 
Magnesia,  composition  of,  57. 
Magnesian  limestone,  149. 
Magnesium,  57. 
Mammals,  age  of,  206. 

"          groups  of,  207-209. 

first  of,  166. 

"          of  bad  lands,  218. 
"          of  the  lias,  188. 
Mammoth  Cave,  130,  131. 
Mammoth,  in  drift,  256,  258. 

"          preserved  in  ice,  257. 
Man,  highest  representative  of  life  on 

this  globe,  322-324. 
"    earliest  remains  of,261,263,266. 
Mantell,  Dr.,  on  fish  of  Monte  Bolca, 

225. 

"        "      on  nebular  theory,  50. 
Marsupialia,  208. 

Martins,    Mr.    Charles,   on    glacial 
striae,  248. 


INDEX. 


341 


Martial,  on  Pompeii,  28. 
Mastodon,  226,  227. 

"         skeletons  of,  found  in  New 

Jersey,  227. 

Mauna  Loa,  ..eruption  of,  35,  36. 
Medina  sandstone,  103. 
Megalichthys,  143. 
Megaceros  Hibernicus,  259. 
Megalosaurus,  191. 
Megalonyx,  237. 
Megatherium,  235,  237. 
M'Enery,  on  Kent's  Hole,  262. 
Metamorphic  rocks,  62,  170. 

"  "      not  always  older 

than  life,  170. 

Metallic  deposits,  in  Silurian  beds,  98. 
Metalliferous  limestone,  129. 
Mica,  an  ingredient  of  granite,  61. 
Micraster  cor-anguinum,  199. 
Middle  Park,  230. 

"        •"       hot-springs  of,  23. 
Miller,  Hugh,  on  universality  of  Del- 
uge, 245. 

Mineral  wealth,  12. 
Miner,  interested  in  geology,  13. 
Miocene,  207,  216-233. 

"        beds,  White-river  basin,  219, 

222. 
"        formation  in  Atlantic  States, 

222. 

"        formation  in  Greenland,  223, 

"        formation  in  Germany,  223. 

Mississippi,  mud  carried  down  by, 

280. 

Mitchell,  on  nebular  theory,  50. 
Mollusca,  77. 
Mollusks,  77. 

"         of  lias,  182. 
"        in  Trenton  limestone,  90. 
Monotremata,  209. 
Monkeys,  fossil,  of  pliocene,  242. 

"      of  Southern  France, 
232. 


Monkeys,  fossil,  of  Sewalik  Hills,  232. 

"          "      of  Greece,  233. 
Monte  Bolca,  fossil  fish  of,  224. 
Mososaurus,  203,  204. 
Mountain  limestone,  127-131. 
Murchison,  on  gradual  appearance 
and  extinction  of  living  beings,  148. 
Muschelkalk,  166,  167. 
Mylodon,  237. 

Nautilus,  184. 

"        and  ammonite,  184-186. 
Neanderthal  skull,  269. 
Nebraska,  bad  lands  of,  217. 
Nebular  theory,  45-50. 
Needham,  17. 
New  Jersey,  soil  of,  12. 

"        "      mastodon  fount  in,  227. 
New  race  of  beings,  322-324. 
New  Eed  Sandstone,  151-168. 
Niagara,  274. 

"        group,  105. 
Nile,  delta  of,  281. 
Noble  Well,  119. 
Nova  Scotia,  trap  of,  17. 
Nummulites,  214. 
Nummulitic  formation,  214. 

CEningen,  223,  225. 

Oil,  in  the  future,  310,  311. 

"    petroleum,  115-122. 
Oldhamia,  82. 
Old  Red  Sandstone,  110. 
Onondaga  salt  group,  106. 
Oolite,  186,  189. 
Order,  in  which  animals  are  found  in 

the  rocks,  79,  80. 
Oreodon,  218. 
Oriskany  sandstone,  111. 
Orthoceratite,  91,  93. 
Ore-forming  processes,  102. 
Ovid,  on  Greek  tradition  of  Deluge, 

45. 


342 


INDEX. 


Owen,  David  Dale,  on  bad  lands 

of  Nebraska,  217. 

Owen,  on  position  of  earliest  verte- 
brates, 80. 

"     on  extinction  of  species,  103. 
"     on  gradual  change  of  living 
"          forms,  148. 
Oxygen,  56. 

Pachydermata,  208. 

Paleotheres,  of  Paris  basin,  211-214. 

of  bad  lands,  218. 
Paleozoic,  147. 
Palisades,  17. 
Pappalardo,  32. 
Paris  basin,  211-214. 
Parahlamoosh  Range,  229. 
Peak  of  Teneriffe,  37. 
Pentamerus,  104. 

"  oblongus,  104. 

Pentacrinus  Briareus,  90. 
Perthe,    discoveries    of,   in   Somme 

Valley,  264. 

Permia,  kingdom  of,  147. 
Permian  beds,  of  England,  149. 

"         "       of  Kansas,  149. 

"        "       of  Germany,  149, 150. 

"         "       of  Russia,  147. 

"        "       formation,  147-151. 
Petroleum,  115-122. 

"          not  new,  115,  116. 

"          theories  of  origin  of,  116, 
117. 

"          its    various    forms,    121, 
122. 

"          produced  by  coral  polyps? 
119-121. 

"          found  in  fossil  corals,  1 20. 

"  where  found,  118. 

"          presence  of,  indicated  by 
gas,  122. 

"          coal,  146,  147. 
Phacops  bufo,  122. 


Philosopher,  geology  of  value    to, 
13. 

Phosphate  of  lime,  57. 

Placoid,  109. 

Placodus,  166. 

Platyrhine,  monkey  of  South  Amejf' 
ca,  242. 

Plesiosaurus,  177,  178. 

Pliny,  on  Vesuvius,  26. 

Pliocene,  207,  233-242. 

Po  and  Adige,  forming  land,  282. 

Pompeii,  26-30. 

Population,  increase  of,  316-318. 

Portage  group,  122. 

Portlock,  Lieut.,  on   volcanic  erup- 
tions, 43. 

Potassium,  57. 

Potash,  composition  of,  57. 

Potsdam  sandstone,  85. 

Prentice,  on  Mammoth  Cave,  131. 

Prestwich,  Mr.,  report  on   Somme- 
valley  discoveries,  263. 

Productus,  141. 

"  pyridiformis,  141. 

Progress,  law  of  the  globe,  296-298. 

Pterodactyle,  179-181. 

"  Cuvieri,  181. 

Pye  Smith,  Dr.,  on  nebular  theory, 

50. 
"        "          "     on  deluge,  245. 

Pythagoras,    on    changes    on    the 
earth's  surface,  272. 

Pterichthys,  113. 

Pterygotus,  107. 

Ptychodus,  203. 

Quadrumana,  207. 
Quartz,  composition  of,  58. 
"       crystals,  88 

Radiata,  70. 

Radiates,  of  cretaceous  period,  199, 
200. 


INDEX. 


343 


Raffles,  Sir  Stamford,  on    eruption 

of  Toraboro,  34. 
Redruth,  tin-mine  at,  19. 
Reptile,  first,  123. 
Reptiles,  of  coal-measures,  143. 
"        Permian,  150. 
"        Connecticut- valley,  160. 
"        Wealden,  189,  190. 
"        cretaceous,  203-205. 
Rhea,  242. 
Rhizopods,     found    in    Laurentian 

rocks,  83. 

Rhinoceros,  two-horned,  259. 
Rhone,  sediment  of  the,  281. 
Rhynchonella  increbescens,  95. 
Ricollet,  on  relics  of  early  men,  264. 
Rink,  Dr.,  on  ice-sheet  of  Greenland, 

249. 
Ripple-marks,  on  Potsdam  sandstone, 

87. 

Rock  cities,  132. 
Rocks,  fire- made,  17. 

"       order  of,  170. 
Rocky  Mountains,  country  west  of, 

17. 

Rodentia,  208. 
Rogers,  H.  D.,  footprints  discovered 

by,  133. 
Ruminantia,  208. 

Salamander,  fossil,  226. 
Salt,  origin  of,  153-157. 

"    in  Dead  Sea,  154. 

"    in  Great  Salt  Lake,  154. 

"    formed  from  the  ocean,  1 54, 1 55. 

<!    at  Droitwich,  152. 

"    at  Cheshire,  152. 

"    at  Cracow,  152. 
Salzworth,  artesian  well  at,  20. 
Satan,  Milton's  description  of,  181. 
Sauropus  primevus,  132. 
Scaphite,  200. 
Scaphites  Ivanii,  200. 


Scoresby,  Mr.,  on  icebergs,  252. 
Scudder,  Mr.  S.  H.,  on  fossil  insects, 

220. 

Sea,  encroachments  of,  275-278. 
Secondary  period,  151-206. 
Segregation,  99. 
Sewalik  Hills,  tertiary  deposits  o£ 

229. 

Shells,  in  chalk,  194. 
Sigillaria,  140. 
Silurian  beds,  71. 

"       period,  84-110. 
Silicon,  56. 
Silica,  56. 

Silver-mine,  Mexico,  19. 
Simond,  M.,  on  Pompeii,  29. 
Siphonia  pyriformis,  200. 
Sivatherium,  229. 
Skapta,  Jokul,  Iceland,  33. 
Skull,  ancient,  in  California,  270. 
Soda,  composition  of,  58. 
Sodium,  58. 
Soil,  age  of,  67. 

"    of  New  Jersey,  12. 
Solenhofen,  quarries  of,  179,  187. 

"  insects  of,  219. 

South    Joggins,   coal-measures    of, 

34. 
Spirifer,  141. 

"        pinguis,  141. 
Springs,  hot,  23. 
Strabo,  on  Vesuvius,  26. 
Sublimation,  100. 
Submergence,  of  land  in  drift  period, 

271,  272. 

Suffolk  Crag,  233. 
Sulphate  of  lime,  57. 
Sulphur,  58. 
Sunderland,  Mass.,  fossil  fish  of,  165. 

"  England,  mine  at,  19. 

Sweden  and  Norway,  change  of  level 

of,  285. 
Syracuse,  salt  of,  107. 


344 


INDEX. 


Tadousac,  old  sea-beaches  of,  286. 

Talc,  59. 

Temperature,  increase  of,  with  depth, 

18,  19. 
Temple,  of  Jupiter  Serapis,  285,  286. 

"        of  Isis  at  Pompeii,  29. 
Teneriffe,  peak  of,  37. 
Terebratula  grandis,  223. 
Tertiary,  beds,  age  of,  68. 

"          period,  206. 
Theory,  nebular,  45-50. 
Thickness,  of  the  earth's  crust,  21. 
Time,  given  to  lower  forms,  291, 292. 
Tin-mines,  Cornwall,  19. 
Tobacco,  not  to  be  used  in  the  future, 

320. 

Tom,  Mount,  155. 
Tortoise,  gigantic,  229. 
Trap-dike,  16. 
Trebra,  M.,  on  formation  of  ores, 

102. 
Trees,  aged,  66. 

"      age  of,  66. 
Trenton  limestone,  89. 
Trias,  151-168. 
Trigonia,  188. 

Trilobite,  86,  87,  94,  122,  149. 
True  veins,  99. 
Turner's  Falls,  160. 
Turrilite,  200. 

"        eostatus,  200. 
Turtles,  fossil,  of  badlands,  217,  218. 
"          "      of  cretaceous  period, 
204. 

Upper  Helderberg  group,  111. 
"      Cambrian,  82. 
"      Silurian,  96-109. 


Vegetable  kingdom,  classes  of,  87. 
Veins,  ^rmation  of,  98. 

"      gash,  99. 

"      true,  99. 
Ventriculite,  200. 
Vertebrata,  79. 
Vesuvius,  26-31. 
Virgil,  on  JEtna,  31. 
Volcanoes,  25-38. 

"        death  of,  297-299,  304, 

305. 
Volcanic  eruptions,  cause  of,  43. 

Waltham,  trap-dikes  of,  17. 
Warm  springs,  of  Baden,  24. 
Water,  the  burning  of,  313. 

"      action  of,  15. 
Wcalden,  189-193. 
Weeds,  disappearance  of,  299,  305, 

306. 

Well,  at  Jakutsk,  18. 
Wells,  artesian,  20. 
Whale,  fossil,  in  Vermont,  271. 
Winslow,  Dr.,  on  earth's  inclination, 

255. 

Wild  beasts,  destruction  of,  299,  300. 
World  not  made  as  it  is,  175-177. 

"       increase  of  land,  surface  of, 
301. 

"       improvement  of  climate  of, 
302,  303. 

"       will  continue,  291-295. 
Wright,  Mr.,  on  recent  formation  of 

carbonate  of  lead,  102. 
Wyandotte  Cave,  130. 

Zeuglodon,  215. 
Zoology,  76-79. 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 
BERKELEY 

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YB  27369 


